Loading station

ABSTRACT

Disclosed herein are methods, devices, and systems for loading and retrieval of particles. In some embodiments, a loading station comprise a tray configured to receive a microwell array, a first magnet, a second magnet, and an actuation mechanism configured to cause movement of at least one of the first magnet and the second magnet.

BACKGROUND Field

The present disclosure relates generally to the field of sample loading,and more particularly, relates to systems, methods, and devices forloading and retrieval of particles.

Description of the Related Art

Methods and techniques such as stochastic barcoding are useful forsingle cell analysis, in particular deciphering gene expression profilesto determine the states of single cells using, for example, reversetranscription, polymerase chain reaction (PCR) amplification, and nextgeneration sequencing (NGS). There is a need for methods and techniquesfor efficient loading of particles, such as barcode-bearing magneticbeads and cells onto a flowcell having one or more microwell arrayssituated therein.

SUMMARY

In some embodiments, a loading station is disclosed. The loading stationincludes a tray configured to receive a microwell array. The loadingstation also includes a first magnet, the first magnet being movablebetween a first magnet active position in which the first magnet ispositioned to exert a first magnetic force in a first direction on oneor more magnetic particles positioned within the microwell array and afirst magnet inactive position in which the first magnet is positionedto exert less magnetic force on the one or more magnetic particlespositioned within the microwell array in comparison to the first magnetactive position, wherein the first magnet is positioned inferior to thetray when the first magnet is in the first magnet active position. Theloading station also includes a second magnet, the second magnet beingmovable between a second magnet active position in which the secondmagnet is positioned to exert a second magnetic force in a seconddirection on the one or more magnetic particles positioned within themicrowell array and a second magnet inactive position in which thesecond magnet is positioned to exert less magnetic force on the one ormore magnetic particles positioned within the microwell array incomparison to the second magnet active position, wherein the seconddirection of the second magnetic force is different than the firstdirection of the first magnetic force. The loading station also includesan actuation mechanism configured to cause movement of at least one ofthe first magnet and the second magnet.

In some embodiments, the actuation mechanism includes an actuator, theactuator being movable between a plurality of different positions,wherein at least some movements of the actuator cause movement of thefirst magnet between the first magnet active position and the firstmagnet inactive position, and wherein at least some movements of theactuator cause movement of the second magnet between the second magnetactive position and the second magnet inactive position. In someembodiments, at least one of the first magnet and the second magnet arecoupled to the actuation mechanism such that when the first magnet is inthe first magnet active position, the second magnet is not in the secondmagnet active position and when the second magnet is in the secondmagnet active position, the first magnet is not in the first magnetactive position. In some embodiments, each movement of the actuator isconfigured to cause the movement of no more than one of the first magnetand the second magnet. In some embodiments, the actuation mechanismincludes one or more members coupled to the first magnet and one or moremembers coupled to the second magnet. In some embodiments, the actuatoris configured to couple to the one or more members coupled to one of thefirst magnet or the second magnet in at least some of the plurality ofdifferent positions of the actuator, wherein the actuator is configuredto decouple from the one or more members coupled to the one of the firstmagnet and the second magnet in at least some of the plurality ofdifferent positions. In some embodiments, the loading station includes adrawer configured to hold one or more tubes, the drawer being movablebetween a plurality of different positions. In some embodiments, thedrawer is movable to at least one position in which at least one of theone or more tubes is positioned to align with an outlet of themicrowell. In some embodiments, the loading station includes a draweractuator, the drawer actuator being movable between a plurality ofdifferent positions, wherein at least some movements of the draweractuator cause movement of the drawer. In some embodiments, themicrowell array is housed within a cartridge and the tray is configuredto receive the cartridge housing the microwell array.

In some embodiments a cartridge can be positioned within the tray of theloading station. In some embodiments, the cartridge includes a flowcell,wherein the flowcell includes the microwell array. In some embodiments,a superior surface of the first magnet is separated from an inferiorsurface of the flowcell by a distance of no more than 1.0 mm when thefirst magnet is positioned in the first magnet active position. In someembodiments, an inferior surface of the second magnet is separated froma superior surface of the flowcell by a distance of no more than 1.0 mmwhen the second magnet is positioned in the second magnet activeposition. In some embodiments, a superior surface of the first magnet isparallel to an inferior surface of the cartridge when the first magnetis in the first magnet active position. In some embodiments, an inferiorsurface of the second magnet is parallel to a superior surface of thecartridge when the second magnet is in the second magnet activeposition. In some embodiments, the loading station includes a lockingmechanism configured to releasably secure the cartridge within the tray.

In some embodiments, a method for collecting a plurality ofbarcode-bearing beads is disclosed. The method includes introducing aplurality of cells into a flowcell of a cartridge positioned within aloading station, introducing a plurality of magnetic barcode-bearingbeads into the flowcell, wherein the flowcell includes a plurality ofmicrowells, wherein each microwell is dimensioned to receive at leastone cell of the plurality of cells and at least one magneticbarcode-bearing bead of the plurality of magnetic barcode-bearing beads,moving a first magnet of the loading station to a position sufficient toexert a first magnetic force on at least some of the magneticbarcode-bearing beads positioned within the plurality of microwells in afirst direction, moving a second magnet of the loading station to aposition sufficient to exert a second magnetic force on at least some ofthe magnetic barcode-bearing beads positioned within the plurality ofmicrowells in a second direction different than the first direction, andintroducing a fluid into the flowcell to cause at least some of thebarcode-bearing beads to flow through the flowcell.

In some embodiments, at least one of the first magnetic force and thesecond magnetic force are of a magnitude sufficient to prevent magneticbarcode-bearing beads on which the at least one of the first magneticforce and second magnetic force are exerted from flowing through theflowcell when the fluid is introduced into the flowcell. In someembodiments, each of the first magnet and the second magnet are coupledto an actuation mechanism includes an actuator. In some embodiments,moving the first magnet of the loading station to exert a first magneticforce on at least some of the magnetic barcode-bearing beads positionedwithin the plurality of microwells in a first direction includes movingthe actuator to a first actuator position. In some embodiments, movingthe second magnet of the loading station to exert a second magneticforce on at least some of the magnetic barcode-bearing beads positionedwithin the plurality of microwells in a second direction different thanthe first direction includes moving the actuator to a second actuatorposition from the first actuator position. In some embodiments, movingthe actuator from the first actuator position to the second actuatorposition causes the first magnet to move to a position in which lessmagnetic force is exerted on the at least some of the magneticbarcode-bearing beads positioned within the plurality of microwells bythe first magnet than when the actuator is positioned within the firstposition.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present disclosure will become more fully apparentfrom the following description and appended claims, taken in conjunctionwith the accompanying drawings. Understanding that these drawings depictonly several embodiments in accordance with the disclosure and are notto be considered limiting of its scope, the disclosure will now bedescribed with additional specificity and detail through use of theaccompanying drawings.

FIG. 1 is a perspective view of a loading station according to anexemplary preferred embodiment.

FIG. 2 is an exploded view of a cartridge that can be used with theloading station of FIG. 1.

FIG. 3 is a cross-sectional view of the cartridge of FIG. 2.

FIG. 4 is a cross-sectional view of a channel of the cartridge of FIG.2.

FIG. 5 is a perspective view of the loading station of FIG. 1 inengagement with the cartridge of FIG. 2.

FIG. 6 is an enlarged view of a section of the loading station andcartridge of FIG. 5.

FIG. 7 is an enlarged view of a section of the loading station andcartridge of FIG. 5 showing internal features.

FIG. 8 is a perspective view of the loading station and cartridge ofFIG. 5.

FIG. 9 is a side view of the loading station and cartridge of FIG. 5showing internal features.

FIG. 10 is an enlarged view of a section of the loading station andcartridge of FIG. 5 showing internal features.

FIG. 11 is a perspective view of the loading station and cartridge ofFIG. 5.

FIG. 12A is a partially exploded perspective view of the loading stationand cartridge of FIG. 5.

FIG. 12B is a partially exploded perspective view of the loading stationand cartridge of FIG. 5.

FIG. 13 is a flowchart depicting an example of a workflow that can beperformed using the loading station and cartridge of FIG. 5.

DETAILED DESCRIPTION

The following detailed description is directed to certain specificembodiments. The invention(s) disclosed herein, however, can be embodiedin a multitude of different ways as defined and covered by the claims.In this description, reference is made to the drawings, wherein likeparts are designated with like numerals throughout. The features,aspects and advantages of the present invention will now be describedwith reference to the drawings of several embodiments that are intendedto be within the scope of the development herein disclosed. These andother embodiments will become readily apparent to those skilled in theart from the following detailed description of the embodiments havingreference to the attached figures, the invention not being limited toany particular embodiment(s) herein disclosed.

All patents, published patent applications, and other publicationsreferred to herein are incorporated by reference in their entirety withrespect to the related technology.

Methods and systems for stochastic barcoding are disclosed. In someembodiments, a device comprises: a flowcell comprising a fluidicchannel, an inlet port, and an outlet port, wherein the fluidic channelcomprises a ceiling, a first sidewall, and a bottom, wherein the contactangle of the ceiling is at least 10 degrees smaller than the contactangle of the first sidewall, wherein the bottom of the fluidic channelcomprises a substrate which comprises a plurality of microwells, andwherein the inlet port and the outlet port are in fluid communicationwith the flowcell via the fluidic channel. The fluidic channel cancomprise a second sidewall. In some embodiments, the hydrophilic coatingis offset from the edge formed by the ceiling and first sidewall by, forexample, 100-1000 micrometers or 1%-25% of the width of the ceiling.Such a device can be used to create plug flow across the width of theflowcell chamber. Plug flow can enable efficient loading and retrievalof particles such as beads and cells into and from microwells of amicrowell array at the bottom of the flowcell chamber.

A superhydrophilic coating or treatment of the top wall (also referredto as ceiling, flowcell ceiling, or fluidic channel ceiling) within thefluidic channel of a flowcell can be used to introduce gas plugs andbuffer plugs to a flowcell with horizontal non-tilting workflow (i.e.,without tilting the flowcell). The superhydrophilic coating providescapillary aided flow for a uniform fluid front of the gas and bufferplug without the use of buoyancy to achieve gas displacement by bufferor to achieve buffer displacement by the gas. Thus, the requirement toutilize buoyancy to displace the gas with buffer or to displace bufferwith the gas, may be eliminated. In turn, the requirement ofnon-horizontal titling workflow of the flow-cell may be eliminated. Insome embodiments, structured hydrophilic and hydrophobic coatings can beused on a flowcell ceiling or a fluidic channel ceiling to tailor theprofile of a gas-buffer fluid front in a flowcell. The selective coating(also referred to as functionalization) of the fluidic channel boundary(also referred to as the flowcell boundary) influences the direction ofcapillary flow within specific portions of the flowcell to control theprofile of the gas-buffer fluid front profile. Capillary aided flow canbe utilized for horizontal operation of a flowcell with gas-buffer plugflow in order to avoid breakdown of the buffer and gas plugs.Additionally, plug flow can be utilized to achieve high flow velocitiesat the flowcell boundaries. One purpose for this may be to flush awayexcess beads on the surface of a microwell array within the flowcell.

Also disclosed herein are methods, systems, and devices for sampleloading. In some embodiments, a method comprises: (a) providing a devicethat comprises: a flowcell comprising a fluidic channel, an inlet port,and an outlet port, wherein the fluidic channel comprises a fluidicchannel ceiling, a first sidewall, and a bottom wherein the contactangle of the fluidic channel ceiling is at least 10 degrees smaller thanthe contact angle of the first sidewall, wherein the bottom comprises asubstrate which comprises a plurality of microwells, wherein theplurality of microwells comprises at least 100 microwells, and whereinthe inlet port and the outlet port are in fluid communication with theflowcell via the fluidic channel; (b) introducing a gas into the fluidicchannel via the inlet port; and (c) introducing a first sample into thefluidic channel via the inlet port, wherein the first sample comprises afirst plurality of particles, and wherein, after introducing the sampleinto the fluidic channel via the inlet port, at least 25% of theplurality of microwells each contains a single particle of the firstplurality of particles. In some embodiments, at least 50% or 75% of theplurality of microwells each contains a single particle of the firstplurality of particles. The fluidic channel can comprise a secondsidewall.

Definitions

Unless defined otherwise, technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the present disclosure belongs. See, e.g. Singleton etal., Dictionary of Microbiology and Molecular Biology 2nd ed., J. Wiley& Sons (New York, N.Y. 1994); Sambrook et al., Molecular Cloning, ALaboratory Manual, Cold Springs Harbor Press (Cold Springs Harbor, N.Y.1989). For purposes of the present disclosure, the following terms aredefined below.

As used herein, the term “adaptor” can mean a sequence to facilitateamplification or sequencing of associated nucleic acids. The associatednucleic acids can comprise target nucleic acids. The associated nucleicacids can comprise one or more of spatial labels, target labels, samplelabels, indexing label, barcodes, stochastic barcodes, or molecularlabels. The adaptors can be linear. The adaptors can be pre-adenylatedadapters. The adaptors can be double- or single-stranded. One or moreadaptor can be located on the 5′ or 3′ end of a nucleic acid. When theadaptors comprise known sequences on the 5′ and 3′ ends, the knownsequences can be the same or different sequences. An adaptor located onthe 5′ and/or 3′ ends of a polynucleotide can be capable of hybridizingto one or more oligonucleotides immobilized on a surface. An adaptercan, in some embodiments, comprise a universal sequence. A universalsequence can be a region of nucleotide sequence that is common to two ormore nucleic acid molecules. The two or more nucleic acid molecules canhave regions of different sequence. Thus, for example, the 5′ adapterscan comprise identical and/or universal nucleic acid sequences and the3′ adapters can comprise identical and/or universal sequences.

As used herein the term “associated” or “associated with” can mean thattwo or more species are identifiable as being co-located at a point intime. An association can mean that two or more species are or werewithin a similar container. An association can be an informaticsassociation, where for example digital information regarding two or morespecies is stored and can be used to determine that one or more of thespecies were co-located at a point in time. An association can be aphysical association. In some embodiments, two or more associatedspecies are “tethered”, “attached”, or “immobilized” to one another orto a common solid or semisolid surface. An association may refer tocovalent or non-covalent means for attaching labels to solid orsemi-solid supports such as beads. An association may be a covalent bondbetween a target and a label.

As used herein, the term “digital counting” can refer to a method forestimating a number of target molecules in a sample. Digital countingcan include the step of determining a number of unique labels that havebeen associated with targets in a sample. This stochastic methodologytransforms the problem of counting molecules from one of locating andidentifying identical molecules to a series of yes/no digital questionsregarding detection of a set of predefined labels.

As used herein, the term “label” or “labels” can refer to nucleic acidcodes associated with a target within a sample. A label can be, forexample, a nucleic acid label. A label can be an entirely or partiallyamplifiable label. A label can be entirely or partially sequencablelabel. A label can be a portion of a native nucleic acid that isidentifiable as distinct. A label can be a known sequence. A label cancomprise a junction of nucleic acid sequences, for example a junction ofa native and non-native sequence. As used herein, the term “label” canbe used interchangeably with the terms, “index”, “tag,” or “label-tag.”Labels can convey information. For example, in various embodiments,labels can be used to determine an identity of a sample, a source of asample, an identity of a cell, and/or a target.

As used herein, the term “nucleic acid” refers to a polynucleotidesequence, or fragment thereof. A nucleic acid can comprise nucleotides.A nucleic acid can be exogenous or endogenous to a cell. A nucleic acidcan exist in a cell-free environment. A nucleic acid can be a gene orfragment thereof. A nucleic acid can be DNA. A nucleic acid can be RNA.A nucleic acid can comprise one or more analogs (e.g. altered backbone,sugar, or nucleobase). Some non-limiting examples of analogs include:5-bromouracil, peptide nucleic acid, xeno nucleic acid, morpholinos,locked nucleic acids, glycol nucleic acids, threose nucleic acids,dideoxynucleotides, cordycepin, 7-deaza-GTP, fluorophores (e.g.rhodamine or fluorescein linked to the sugar), thiol containingnucleotides, biotin linked nucleotides, fluorescent base analogs, CpGislands, methyl-7-guanosine, methylated nucleotides, inosine,thiouridine, pseudouridine, dihydrouridine, queuosine, and wyosine.“Nucleic acid”, “polynucleotide, “target polynucleotide”, and “targetnucleic acid” can be used interchangeably.

As used herein, the term “sample” can refer to a composition comprisingtargets. Suitable samples for analysis by the disclosed methods,devices, and systems include cells, tissues, organs, or organisms.

As used herein, the term “sampling device” or “device” can refer to adevice which may take a section of a sample and/or place the section ona substrate. A sample device can refer to, for example, a fluorescenceactivated cell sorting (FACS) machine, a cell sorter machine, a biopsyneedle, a biopsy device, a tissue sectioning device, a microfluidicdevice, a blade grid, and/or a microtome.

As used herein, the term “solid support” can refer to discrete solid orsemi-solid surfaces to which a plurality of stochastic barcodes may beattached. A solid support may encompass any type of solid, porous, orhollow sphere, ball, bearing, cylinder, or other similar configurationcomposed of plastic, ceramic, metal, or polymeric material (e.g.,hydrogel) onto which a nucleic acid may be immobilized (e.g., covalentlyor non-covalently). A solid support may comprise a discrete particlethat may be spherical (e.g., microspheres) or have a non-spherical orirregular shape, such as cubic, cuboid, pyramidal, cylindrical, conical,oblong, or disc-shaped, and the like. A plurality of solid supportsspaced in an array may not comprise a substrate. A solid support may beused interchangeably with the term “bead.”

A solid support can refer to a “substrate.” A substrate can be a type ofsolid support. A substrate can refer to a continuous solid or semi-solidsurface on which the methods of the disclosure may be performed. Asubstrate can refer to an array, a cartridge, a chip, a device, and aslide, for example.

As used herein, the term “stochastic barcode” can refer to apolynucleotide sequence comprising labels. A stochastic barcode can be apolynucleotide sequence that can be used for stochastic barcoding.Stochastic barcodes can be used to quantify targets within a sample.Stochastic barcodes can be used to control for errors which may occurafter a label is associated with a target. For example, a stochasticbarcode can be used to assess amplification or sequencing errors. Astochastic barcode associated with a target can be called a stochasticbarcode-target or stochastic barcode-tag-target.

As used herein, the term “gene-specific stochastic barcode” can refer toa polynucleotide sequence comprising labels and a target-binding regionthat is gene-specific. A stochastic barcode can be a polynucleotidesequence that can be used for stochastic barcoding. Stochastic barcodescan be used to quantify targets within a sample. Stochastic barcodes canbe used to control for errors which may occur after a label isassociated with a target. For example, a stochastic barcode can be usedto assess amplification or sequencing errors. A stochastic barcodeassociated with a target can be called a stochastic barcode-target orstochastic barcode-tag-target.

As used herein, the term “stochastic barcoding” can refer to the randomlabeling (e.g., barcoding) of nucleic acids. Stochastic barcoding canutilize a recursive Poisson strategy to associate and quantify labelsassociated with targets. As used herein, the term “stochastic barcoding”can be used interchangeably with “gene-specific stochastic barcoding.”

As used here, the term “target” can refer to a composition which can beassociated with a stochastic barcode. Exemplary suitable targets foranalysis by the disclosed methods, devices, and systems includeoligonucleotides, DNA, RNA, mRNA, microRNA, tRNA, and the like. Targetscan be single or double stranded. In some embodiments targets can beproteins. In some embodiments targets are lipids.

Stochastic Barcodes

Stochastic barcoding has been described in, for example, US20150299784,WO2015031691, and Fu et al, Proc Natl Acad Sci U.S.A. 2011 May 31;108(22):9026-31, the content of these publications is incorporatedhereby in its entirety. Briefly, a stochastic barcode can be apolynucleotide sequence that may be used to stochastically label (e.g.,barcode, tag) a target. A stochastic barcode can comprise one or morelabels. Exemplary labels can include a universal label, a cellularlabel, a molecular label, a sample label, a plate label, a spatiallabel, and/or a pre-spatial label. The stochastic barcode can comprise a5′amine that may link the stochastic barcode to a solid support. Thestochastic barcode can comprise a universal label, a dimension label, aspatial label, a cellular label, and/or a molecular label. The order ofdifferent labels (including but not limited to the universal label, thedimension label, the spatial label, the cellular label, and the moleculelabel) in the stochastic barcode can vary. For example, the universallabel may be the 5′-most label, and the molecular label may be the3′-most label. The spatial label, dimension label, and the cellularlabel may be in any order. In some embodiments, the universal label, thespatial label, the dimension label, the cellular label, and themolecular label are in any order.

The stochastic barcodes can be from a “non-depleting reservoirs,” a poolof stochastic barcodes made up of many different labels. A non-depletingreservoir can comprise large numbers of different stochastic barcodessuch that when the non-depleting reservoir is associated with a pool oftargets each target is likely to be associated with a unique stochasticbarcode. The uniqueness of each labeled target molecule can bedetermined by the statistics of random choice, and depends on the numberof copies of identical target molecules in the collection compared tothe diversity of labels. The size of the resulting set of labeled targetmolecules can be determined by the stochastic nature of the barcodingprocess, and analysis of the number of stochastic barcodes detected thenallows calculation of the number of target molecules present in theoriginal collection or sample. When the ratio of the number of copies ofa target molecule present to the number of unique stochastic barcodes islow, the labeled target molecules are highly unique (i.e. there is avery low probability that more than one target molecule will have beenlabeled with a given label).

A label, for example the cellular label, can comprise a unique set ofnucleic acid sub-sequences of defined length, e.g. seven nucleotideseach (equivalent to the number of bits used in some Hamming errorcorrection codes), which can be designed to provide error correctioncapability. The set of error correction sub-sequences comprise sevennucleotide sequences can be designed such that any pairwise combinationof sequences in the set exhibits a defined “genetic distance” (or numberof mismatched bases), for example, a set of error correctionsub-sequences can be designed to exhibit a genetic distance of threenucleotides. In this case, review of the error correction sequences inthe set of sequence data for labeled target nucleic acid molecules(described more fully below) can allow one to detect or correctamplification or sequencing errors. In some embodiments, the length ofthe nucleic acid sub-sequences used for creating error correction codescan vary, for example, they can be, or be about 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 15, 20, 30, 31, 40, 50, or a number or a range between any two ofthese values, nucleotides in length. In some embodiments, nucleic acidsub-sequences of other lengths can be used for creating error correctioncodes.

The stochastic barcode can comprise a target-binding region. Thetarget-binding region can interact with a target in a sample. The targetcan be, or comprise, ribonucleic acids (RNAs), messenger RNAs (mRNAs),microRNAs, small interfering RNAs (siRNAs), RNA degradation products,RNAs each comprising a poly(A) tail, and any combination thereof. Insome embodiments, the plurality of targets can include deoxyribonucleicacids (DNAs).

In some embodiments, a target-binding region can comprise an oligo(dT)sequence which can interact with poly(A) tails of mRNAs. One or more ofthe labels of the stochastic barcode (e.g., the universal label, thedimension label, the spatial label, the cellular label, and themolecular label) can be separated by a spacer from another one or two ofthe remaining labels of the stochastic barcode. The spacer can be, forexample, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, or 20 or more nucleotides. In some embodiments, none of the labelsof the stochastic barcode is separated by spacer.

A stochastic barcode can comprise one or more universal labels, one ormore dimension labels, one or more spatial labels, one or more cellularlabels, one or more molecular labels, one or more target bindingregions, or any combination thereof.

The one or more universal labels can be the same for all stochasticbarcodes in the set of stochastic barcodes attached to a given solidsupport (e.g., beads), or the same for all stochastic barcodes attachedto a plurality of beads. A universal label can comprise a nucleic acidsequence that is capable of hybridizing to a sequencing primer. Auniversal label can comprise a nucleic acid sequence that is capable ofhybridizing to a PCR primer, or comprise a nucleic acid sequence that iscapable of hybridizing to a sequencing primer and a PCR primer. Thenucleic acid sequence of the universal label that is capable ofhybridizing to a sequencing or PCR primer can be referred to as a primerbinding site. A universal label can comprise a sequence that can be usedto initiate transcription of the stochastic barcode. A universal labelcan comprise a sequence that can be used for extension of the stochasticbarcode or a region within the stochastic barcode.

A dimension label can comprise a nucleic acid sequence that providesinformation about a dimension in which the stochastic labeling occurred.For example, a dimension label can provide information about the time atwhich a target was stochastically barcoded. A dimension label can beassociated with a time of stochastic barcoding in a sample. A dimensionlabel can be activated at the time of stochastic labeling. Differentdimension labels can be activated at different times. The dimensionlabel provides information about the order in which targets, groups oftargets, and/or samples were stochastically barcoded. For example, apopulation of cells can be stochastically barcoded at the G0 phase ofthe cell cycle. The cells can be pulsed again with stochastic barcodesat the G1 phase of the cell cycle. The cells can be pulsed again withstochastic barcodes at the S phase of the cell cycle, and so on.Stochastic barcodes at each pulse (e.g., each phase of the cell cycle),can comprise different dimension labels. In this way, the dimensionlabel provides information about which targets were labeled at whichphase of the cell cycle. Dimension labels can interrogate many differentbiological times. Exemplary biological times can include, but are notlimited to, the cell cycle, transcription (e.g., transcriptioninitiation), and transcript degradation. In another example, a sample(e.g., a cell, a population of cells) can be stochastically labeledbefore and/or after treatment with a drug and/or therapy. The changes inthe number of copies of distinct targets can be indicative of thesample's response to the drug and/or therapy.

A dimension label can be activatable. An activatable dimension label canbe activated at a specific time point. The activatable label can be, forexample, constitutively activated (e.g., not turned off). Theactivatable dimension label can be, for example, reversibly activated(e.g., the activatable dimension label can be turned on and turned off).

A spatial label can comprise a nucleic acid sequence that providesinformation about the spatial orientation of a target molecule which isassociated with the stochastic barcode. A spatial label can beassociated with a coordinate in a sample. The coordinate can be a fixedcoordinate. For example a coordinate can be fixed in reference to asubstrate. A spatial label can be in reference to a two orthree-dimensional grid. A coordinate can be fixed in reference to alandmark. The landmark can be identifiable in space. A landmark can be astructure which can be imaged. A landmark can be a biological structure,for example an anatomical landmark; or a cellular landmark, for instancean organelle. A landmark can be a non-natural landmark such as astructure with an identifiable identifier such as a color code, barcode, magnetic property, fluorescents, radioactivity, or a unique sizeor shape. A spatial label can be associated with a physical partition(e.g. a well, a container, or a droplet). In some embodiments, multiplespatial labels are used together to encode one or more positions inspace. The spatial label can be identical for all stochastic barcodesattached to a given solid support (e.g., bead), but different fordifferent solid supports (e.g., beads). A cellular label can comprise anucleic acid sequence that provides information for determining whichtarget nucleic acid originated from which cell. In some embodiments, thecellular label is identical for all stochastic barcodes attached to agiven solid support (e.g., bead), but different for different solidsupports (e.g., beads). In some embodiments, the percentage ofstochastic barcodes on the same solid support comprising the samecellular label can be, or be about 60%, 70%, 80%, 85%, 90%, 95%, 97%,99%, 100%, or a number or a range between any two of these values. Forexample, at least 95% of stochastic barcodes on the same solid supportcan comprise the same cellular label.

A molecular label can comprise a nucleic acid sequence that providesidentifying information for the specific type of target nucleic acidspecies hybridized to the stochastic barcode. A molecular label cancomprise a nucleic acid sequence that provides a counter for thespecific occurrence of the target nucleic acid species hybridized to thestochastic barcode (e.g., target-binding region). In some embodiments, adiverse set of molecular labels are attached to a given solid support(e.g., bead). In some embodiments, there can be, or be about, 10², 10³,10⁴, 10⁵, 10⁶, 10⁷, 10⁸, 10⁹, or a number or a range of unique molecularlabel sequences. For example, a plurality of stochastic barcodes cancomprise about 6561 molecular labels with distinct sequences. As anotherexample, a plurality of stochastic barcodes can comprise about 65536molecular labels with distinct sequences. In some embodiments, there canbe at least, or at most, 10², 10³, 10⁴, 10⁵, 10⁶, 10⁷, 10⁸, or 10⁹,unique molecular label sequences. The unique molecular label sequencesattached to a given solid support (e.g., bead).

A target-binding region can hybridize with a target of interest. In someembodiments, the target binding regions can comprise a nucleic acidsequence that hybridizes specifically to a target (e.g. target nucleicacid, target molecule, e.g., a cellular nucleic acid to be analyzed),for example to a specific gene sequence. In some embodiments, a targetbinding region can comprise a nucleic acid sequence that can attach(e.g., hybridize) to a specific location of a specific target nucleicacid. In some embodiments, the target binding region can comprise anucleic acid sequence that is capable of specific hybridization to arestriction enzyme site overhang (e.g. an EcoRI sticky-end overhang).The stochastic barcode can then ligate to any nucleic acid moleculecomprising a sequence complementary to the restriction site overhang.

In some embodiments, a target binding region can comprise a non-specifictarget nucleic acid sequence. A non-specific target nucleic acidsequence can refer to a sequence that can bind to multiple targetnucleic acids, independent of the specific sequence of the targetnucleic acid. For example, target binding region can comprise a randommultimer sequence, or an oligo(dT) sequence that hybridizes to thepoly(A) tail on mRNA molecules. A random multimer sequence can be, forexample, a random dimer, trimer, quatramer, pentamer, hexamer, septamer,octamer, nonamer, decamer, or higher multimer sequence of any length. Insome embodiments, the target binding region is the same for allstochastic barcodes attached to a given bead. In some embodiments, thetarget binding regions for the plurality of stochastic barcodes attachedto a given bead can comprise two or more different target bindingsequences. A target binding region can be, or be about, 5, 10, 15, 20,25, 30, 35, 40, 45, 50, or a number or a range between any two of thesevalues, nucleotides in length. A target binding region can be at mostabout 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 or more nucleotides inlength.

In some embodiments, a target-binding region can comprise an oligo(dT)which can hybridize with mRNAs comprising poly-adenylated ends. Atarget-binding region can be gene-specific. For example, atarget-binding region can be configured to hybridize to a specificregion of a target. A target-binding region can be, or be about, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26 27, 28, 29, 30, or a number or a range between any two ofthese values, nucleotides in length. A target-binding region can be atleast, or at most, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26 27, 28, 29, or 30,nucleotides in length. A target-binding region can be about 5-30nucleotides in length. When a stochastic barcode comprises agene-specific target-binding region, the stochastic barcode can bereferred to as a gene-specific stochastic barcode.

Solid Supports

Stochastic barcodes disclosed herein can, in some embodiments, beassociated with a solid support. The solid support can be, for example,a synthetic particle. In some embodiments, some or all of the molecularlabels (e.g., the first molecular labels) of a plurality of stochasticbarcodes (e.g., the first plurality of stochastic barcodes) on a solidsupport differ by at least one nucleotide. The cellular labels of thestochastic barcodes on the same solid support can be the same. Thecellular labels of the stochastic barcodes on different solid supportscan differ by at least one nucleotide. For example, first cellularlabels of a first plurality of stochastic barcodes on a first solidsupport can have the same sequence, and second cellular labels of asecond plurality of stochastic barcodes on a second solid support canhave the same sequence. The first cellular labels of the first pluralityof stochastic barcodes on the first solid support and the secondcellular labels of the second plurality of stochastic barcodes on thesecond solid support can differ by at least one nucleotide. A cellularlabel can be, for example, about 5-20 nucleotides long. A molecularlabel can be, for example, about 5-20 nucleotides long.

The synthetic particle can be, for example, a bead. The bead can be, forexample, a silica gel bead, a controlled pore glass bead, a magneticbead, a Dynabead, a Sephadex/Sepharose bead, a cellulose bead, apolystyrene bead, or any combination thereof. The bead can comprise amaterial such as polydimethylsiloxane (PDMS), polystyrene, glass,polypropylene, agarose, gelatin, hydrogel, paramagnetic, ceramic,plastic, glass, methylstyrene, acrylic polymer, titanium, latex,sepharose, cellulose, nylon, silicone, or any combination thereof.

For example, after introducing cells such as single cells onto aplurality of microwells of a microwell array, beads can be introducedonto the plurality of microwells of the microwell array. Each microwellcan comprise one bead. The beads can comprise a plurality of stochasticbarcodes. A stochastic barcode can comprise a 5′ amine region attachedto a bead. The stochastic barcode can comprise a universal label, amolecular label, a target-binding region, or any combination thereof.

The stochastic barcodes disclosed herein can be associated to (e.g.,attached to) a solid support (e.g., a bead). The stochastic barcodesassociated with a solid support can each comprise a molecular labelselected from a group comprising at least 100 or 1000 molecular labelswith unique sequences. In some embodiments, different stochasticbarcodes associated with a solid support can comprise molecular labelsof different sequences. In some embodiments, a percentage of stochasticbarcodes associated with a solid support comprises the same cell label.For example, the percentage can be, or be about 60%, 70%, 80%, 85%, 90%,95%, 97%, 99%, 100%, or a number or a range between any two of thesevalues. As another example, the percentage can be at least, or at most60%, 70%, 80%, 85%, 90%, 95%, 97%, 99%, or 100%. In some embodiments,stochastic barcodes associated with a solid support can have the samecell label. The stochastic barcodes associated with different solidsupports can have different cell labels selected from a group comprisingat least 100 or 1000 cell labels with unique sequences.

In some embodiments, stochastically barcoding the plurality of targetsin the sample can be performed with a solid support including aplurality of synthetic particles associated with the plurality ofstochastic barcodes. In some embodiments, the solid support can includea plurality of synthetic particles associated with the plurality ofstochastic barcodes. The spatial labels of the plurality of stochasticbarcodes on different solid supports can differ by at least onenucleotide. The solid support can, for example, include the plurality ofstochastic barcodes in two dimensions or three dimensions. The syntheticparticles can be beads. The beads can be silica gel beads, controlledpore glass beads, magnetic beads, Dynabeads, Sephadex/Sepharose beads,cellulose beads, polystyrene beads, or any combination thereof. Thesolid support can include a polymer, a matrix, a hydrogel, a needlearray device, an antibody, or any combination thereof. In someembodiments, the solid supports can be free floating. In someembodiments, the solid supports can be embedded in a semi-solid or solidarray. The stochastic barcodes may not be associated with solidsupports. The stochastic barcodes can be individual nucleotides. Thestochastic barcodes can be associated with a substrate.

As used herein, the terms “tethered”, “attached”, and “immobilized” areused interchangeably, and can refer to covalent or non-covalent meansfor attaching stochastic barcodes to a solid support. Any of a varietyof different solid supports can be used as solid supports for attachingpre-synthesized stochastic barcodes or for in situ solid-phase synthesisof stochastic barcode.

In some embodiments, the solid support is a bead. The bead can compriseone or more types of solid, porous, or hollow sphere, ball, bearing,cylinder, or other similar configuration which a nucleic acid can beimmobilized (e.g., covalently or non-covalently). The bead can be, forexample, composed of plastic, ceramic, metal, polymeric material, or anycombination thereof. A bead can be, or comprise, a discrete particlethat is spherical (e.g., microspheres) or have a non-spherical orirregular shape, such as cubic, cuboid, pyramidal, cylindrical, conical,oblong, or disc-shaped, and the like. In some embodiments, a bead can benon-spherical in shape.

Beads can comprise a variety of materials including, but not limited to,paramagnetic materials (e.g. magnesium, molybdenum, lithium, andtantalum), superparamagnetic materials (e.g. ferrite (Fe₃O₄; magnetite)nanoparticles), ferromagnetic materials (e.g. iron, nickel, cobalt, somealloys thereof, and some rare earth metal compounds), ceramic, plastic,glass, polystyrene, silica, methylstyrene, acrylic polymers, titanium,latex, sepharose, agarose, hydrogel, polymer, cellulose, nylon, and anycombination thereof. In some embodiments, the bead (e.g., the bead towhich the stochastic labels are attached) is a hydrogel bead. In someembodiments, the bead comprises hydrogel.

The size of the beads can vary. For example, the diameter of the beadcan range from 0.1 micrometer to 50 micrometers. In some embodiments,the diameters of beads can be, or be about, 0.1, 0.5, 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 20, 30, 40, 50 micrometers, or a number or a range betweenany two of these values.

The diameters of the bead can be related to the diameter of the wells ofthe substrate. In some embodiments, the diameters of the bead can be, orbe about, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or a numberor a range between any two of these values, longer or shorter than thediameter of the well. The diameter of the beads can be related to thediameter of a cell (e.g., a single cell entrapped by a well of thesubstrate). In some embodiments, the diameters of the beads can be, orbe about, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%,250%, 300%, or a number or a range between any two of these values,longer or shorter than the diameter of the cell.

A bead can be attached to and/or embedded in a substrate. A bead can beattached to and/or embedded in a gel, hydrogel, polymer and/or matrix.The spatial position of a bead within a substrate (e.g., gel, matrix,scaffold, or polymer) can be identified using the spatial label presenton the stochastic barcode on the bead which can serve as a locationaddress.

Examples of beads can include, but are not limited to, streptavidinbeads, agarose beads, magnetic beads, Dynabeads®, MACS® microbeads,antibody conjugated beads (e.g., anti-immunoglobulin microbeads),protein A conjugated beads, protein G conjugated beads, protein A/Gconjugated beads, protein L conjugated beads, oligo(dT) conjugatedbeads, silica beads, silica-like beads, anti-biotin microbeads,anti-fluorochrome microbeads, and BcMag™ Carboxyl-Terminated MagneticBeads.

A bead can be associated with (e.g. impregnated with) quantum dots orfluorescent dyes to make it fluorescent in one fluorescence opticalchannel or multiple optical channels. A bead can be associated with ironoxide or chromium oxide to make it paramagnetic or ferromagnetic. Beadscan be identifiable. For example, a bead can be imaged using a camera. Abead can have a detectable code associated with the bead. For example, abead can comprise a stochastic barcode. A bead can change size, forexample due to swelling in an organic or inorganic solution. A bead canbe hydrophobic. A bead can be hydrophilic. A bead can be biocompatible.

A solid support (e.g., bead) can be visualized. The solid support cancomprise a visualizing tag (e.g., fluorescent dye). A solid support(e.g., bead) can be etched with an identifier (e.g., a number). Theidentifier can be visualized through imaging the beads.

Substrates and Microwell Arrays

As used herein, a substrate can refer to a type of solid support. Asubstrate can refer to a solid support that can comprise stochasticbarcodes of the disclosure. A substrate can, for example, comprise aplurality of microwells. For example, a substrate can be a well arraycomprising two or more microwells. In some embodiments, a microwell cancomprise a small reaction chamber of defined volume. In someembodiments, a microwell can entrap one or more cells. In someembodiments, a microwell can entrap only one cell. In some embodiments,a microwell can entrap one or more solid supports. In some embodiments,a microwell can entrap only one solid support. In some embodiments, amicrowell entraps a single cell and a single solid support (e.g., bead).In some embodiments, a microwell can contain a single particle (e.g., acell or a bead). In some embodiments, a microwell can contain twodifferent particles (e.g., a cell and a bead).

Microwell Shapes

Microwells can be fabricated in a variety of shapes. Non-limitingexemplary well geometries can include cylindrical, conical,hemispherical, rectangular, or polyhedral (e.g., three dimensionalgeometries comprised of several planar faces, for example, hexagonalcolumns, octagonal columns, inverted triangular pyramids, invertedsquare pyramids, inverted pentagonal pyramids, inverted hexagonalpyramids, or inverted truncated pyramids). The microwells can comprise ashape that combines two or more of these geometries. For example, amicrowell can be partly cylindrical, with the remainder having the shapeof an inverted cone. A microwell can include two side-by-side cylinders,one of larger diameter (e.g. that corresponds roughly to the diameter ofthe beads) than the other (e.g. that corresponds roughly to the diameterof the cells), that are connected by a vertical channel (that is,parallel to the cylinder axes) that extends the full length (depth) ofthe cylinders. The location of the opening of the microwell can vary.For example, the opening of the microwell can be at the upper surface ofthe substrate. For example, the opening of the microwell can be at thelower surface of the substrate. The shape of the close end, for examplethe bottom, of the microwell can vary. For example, the closed end ofthe microwell can be flat. For example, the closed end of the microwellcan have a curved surface (e.g., convex or concave). The shape and/orsize of the microwell can be determined based on the types of cells orsolid supports to be trapped within the microwells. In some embodiments,a microwell can have a non-circular cross section (e.g., square orhexagonal) in a plane of the substrate.

Microwell Sizes

Microwells can be fabricated in a variety of sizes. Microwell size canbe characterized, for example, in terms of the diameter and/or the depthof the microwells. The diameter of the microwell can refer to thelargest circle that can be inscribed within the planar cross-section ofthe microwell geometry. The diameter of the microwells can, in someembodiments, range from about 1-fold to about 10-folds the diameter ofthe cells or solid supports to be trapped within the microwells. In someembodiments, the microwell diameter can be, or be about, 1-fold,1.5-fold, 2-folds, 3-folds, 4-folds, 5-folds, 6-folds, 7-folds, 8-folds,9-files, 10-folds, or a number or a range between any two of thesevalues, the diameter of the cells or the solid supports to be trappedwithin the microwells. In some embodiments, the microwell diameter canbe at least, or at most, 1-fold, 1.5-fold, 2-folds, 3-folds, 4-folds,5-folds, 6-folds, 7-folds, 8-folds, 9-files, 10-folds the diameter ofthe cells or the solid supports to be trapped within the microwells. Insome embodiments, the microwell diameter can be about 2.5-folds thediameter of the cells or solid supports to be trapped within themicrowells.

The diameter of a microwell can be specified in terms of absolutedimensions. The diameter of a microwell can range from about 1 nanometerto about 1000 micrometers. In some embodiments, the microwell diametercan be, or be about, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60,70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000micrometers, or a number or a range between any two of these values. Insome embodiments, the microwell diameter can be at least, or at most, 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200,300, 400, 500, 600, 700, 800, 900, 1000 micrometers. In someembodiments, the microwell diameter can be, or be about, 1, 2, 3, 4, 5,6, 7, 8, 9 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500,600, 700, 800, 900, 1000 micrometers, or a number or a range between anytwo of these values. In some embodiments, the microwell diameter can beat least, or at most 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60,70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000micrometers. In some embodiments, the microwell diameter can be about 30micrometers.

The depth of the microwell can vary, for example, to provide efficienttrapping of droplets, for example cells and solid supports, or toprovide efficient exchange of assay buffers and other reagents containedwithin the wells. The ratio of diameter to depth (i.e. aspect ratio) canbe varied such that once a cell and/or a solid support settle inside amicrowell, they will not be displaced by fluid motion above themicrowell. In some embodiments, the depth of the microwell can besmaller than the diameter of the bead. For example, the depth of themicrowell can be, or be about, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%,80%, 90%, 99%, 99.9%, 100%, or a number or a range between any two ofthese values, of the diameter of the bead. For example, the depth of themicrowell can be at least, or at most, 5%, 10%, 20%, 30%, 40%, 50%, 60%,70%, 80%, 90%, 99%, 99.9%, 100% of the diameter of the bead. In someembodiments, synthetic particles such as beads can protrude outside ofthe microwells.

In some embodiments, a dimension of a microwell allows the microwell tocontain at most one bead. A ratio of the width of the microwell to adiameter of the bead can vary, ranging from 1-1.9. In some embodiments,the ratio of the width of the microwell to the diameter of the bead canbe, or be about, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or anumber or a range between any two of these values. In some embodiments,the ratio of the width of the microwell to the diameter of the bead canbe at least, or at most, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or1.9.

The dimensions of a microwell can vary such that the microwell hassufficient space to accommodate a solid support and a cell of varioussizes without being dislodged by fluid motion above the microwell. Thedepth of a microwell can range from about 1-fold to about 10-folds thediameter of the cells or solid supports to be trapped within themicrowells. In some embodiments, the microwell depth can be, or beabout, 1-fold, 1.5-fold, 2-folds, 3-folds, 4-folds, 5-folds, 6-folds,7-folds, 8-folds, 9-files, 10-folds, or a number or a range between anytwo of these values, the diameter of the cells or solid supports to betrapped within the microwells. In some embodiments, the microwell depthcan be at least, or at most, 1-fold, 1.5-fold, 2-folds, 3-folds,4-folds, 5-folds, 6-folds, 7-folds, 8-folds, 9-files, or 10-folds thediameter of the cells or solid supports to be trapped within themicrowells. In some embodiments, the microwell depth can be about2.5-folds the diameter of the cells or solid supports to be trappedwithin the microwells.

An aspect ratio of the width of the microwell to the depth of themicrowell can vary, for example ranging from 0.1-2. In some embodiments,the aspect ratio of the width of the microwell to the depth of themicrowell can be, or be about, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or a number or arange between any two of these values. In some embodiments, the aspectratio of the width of the microwell to the depth of the microwell can beat least, or at most, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.

The depth of a microwell can be specified in terms of its absolutedimension. For example, the depth of a microwell can range from about 1nanometer to about 1000 micrometers. In some embodiments, the microwelldepth can be, or be about, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40,50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000micrometers, or a number or a range between any two of these values. Insome embodiments, the microwell depth can be at least, or at most, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300,400, 500, 600, 700, 800, 900, 1000 micrometers. In some embodiments, themicrowell depth can be, or be about, 1, 2, 3, 4, 5, 6, 7, 8, 9 10, 20,30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900,1000 micrometers, or a number or a range between any two of thesevalues. In some embodiments, the microwell depth can be at least, or atmost, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90,100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 micrometers. In someembodiments, the microwell depth can be about 30 micrometers.

The volume of a microwell can vary, for example ranging from about 1picoliter to about 1000 microliters. In some embodiments, the microwellvolume can be, or be about, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40,50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000,or a number or a range between any two of these values, picoliters. Insome embodiments, the microwell volume can be at least, or at most, 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200,300, 400, 500, 600, 700, 800, 900, or 1000 picoliters. In someembodiments, the microwell volume can be, or be about, 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500,600, 700, 800, 900, 1000, or a number or a range between any two ofthese values, nanoliters. In some embodiments, the microwell volume canbe at least, or at most, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50,60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000nanoliters. In some embodiments, the microwell volume can be, or beabout, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90,100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, or a number or arange between any two of these values, microliters. In some embodiments,the microwell volume can be at least, or at most, 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600,700, 800, 900, or 1000. In some embodiments, the microwell volume can beabout 1 microliter.

The volume of a microwell can be characterized in terms of the variationin volume from one microwell to another. The coefficient of variation(expressed as a percentage) for microwell volume can range from about 1%to about 100%. The coefficient of variation for microwell volume can be,or be about, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%,50%, 60%, 70%, 80%, 90%, 100%, or a number or a range between any two ofthese values. The coefficient of variation for microwell volume can be,at least or at most, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%,40%, 50%, 60%, 70%, 80%, 90%, or 100%. In some embodiments, thecoefficient of variation of microwell volume can be about 2.5%.

The ratio of the volume of a microwell to the surface area of a bead (orto the surface area of a solid support to which stochastic barcodeoligonucleotides can be attached) can vary, for example range from about2.5 to about 1520 micrometers. In some embodiments, the ratio can be, orbe about, 2.5, 5, 10, 100, 500, 750, 1000, 1520 micrometers, or a numberor a range between any two of these values. In some embodiments, theratio can be at least, or at most, 2.5, 5, 10, 100, 500, 750, 1000, or1520 micrometers. In some embodiments, the ratio can be about 67.5micrometers.

Microwell Arrangements

Microwells can be arranged in a one dimensional, two dimensional, orthree-dimensional array. A three dimensional array can be achieved, forexample, by stacking a series of two or more two dimensional arrays, forexample by stacking two or more substrates comprising microwell arrays.

The pattern and spacing between microwells can vary to optimize theefficiency of trapping a single cell and a single solid support (e.g.,bead) in each well, as well as to maximize the number of wells per unitarea of the array. The microwells can be distributed according to avariety of random or non-random patterns. For example, they can bedistributed entirely randomly across the surface of the array substrate,or they can be arranged in a square grid, rectangular grid, hexagonalgrid, or the like.

The center-to-center distance or the center-to-center spacing betweenwells can vary from about 1 micrometer to about 1000 micrometers. Insome embodiments, the center-to-center distance between wells can be, orbe about, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90,100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 micrometers, or anumber or a range between any two of these values. In some embodiments,the center-to-center distance between wells can be at least, or at most,1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200,300, 400, 500, 600, 700, 800, 900, or 1000 micrometers. In someembodiments, the center-to-center distance between wells can be about4890 micrometers.

The distance or the spacing between the edges of the microwells can varyfrom about 1 micrometer to about 1000 micrometers. In some embodiments,the distance between the edges of the wells can be, or be about, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300,400, 500, 600, 700, 800, 900, 1000 micrometers, or a number or a rangebetween any two of these values. In some embodiments, the distancebetween the edges of the wells can be at least, or at most, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400,500, 600, 700, 800, 900, or 1000 micrometers. In some embodiments, thedistance between the edges of the wells can be about 80 micrometers.

Microwell Density

A microwell array can comprise microwells at varying densities, forexample ranging from 100 microwells per inch² to 1000000 microwells perinch². In some embodiments, the density of the microwell array can be,or be about, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000,3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000,50000, 60000, 70000, 80000, 90000, 100000, 200000, 300000, 400000,500000, 600000, 700000, 800000, 900000, 1000000, 2000000, 3000000,4000000, 5000000, 6000000, 7000000, 8000000, 9000000, 10000000, or anumber or a range between any two of these values, microwells per inch².In some embodiments, the density of the microwell array can be at least,or at most, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000,3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000,50000, 60000, 70000, 80000, 90000, 100000, 200000, 300000, 400000,500000, 600000, 700000, 800000, 900000, 1000000, 2000000, 3000000,4000000, 5000000, 6000000, 7000000, 8000000, 9000000, or 10000000microwells per inch². In some embodiments, the density of the microwellarray can be, or be about, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200,300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000,7000, 8000, 9000, 10000, 20000, 30000, 40000, 50000, 60000, 70000,80000, 90000, 100000, or a number or a range between any two of thesevalues, microwells per cm². In some embodiments, the density of themicrowell array can be at least, or at most, 10, 20, 30, 40, 50, 60, 70,80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000,4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000, 50000,60000, 70000, 80000, 90000, or 100000 microwells per cm².

The total number of microwells on a substrate can vary based on thepattern and the spacing of the wells and the overall dimensions of thearray. The number of microwells in the array can vary, for example,ranging from about 96 to about 1000000. In some embodiments, the numberof microwells in the microarray can be, or be about, 96, 384, 1536,2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000,40000, 50000, 60000, 70000, 80000, 90000, 100000, 200000, 300000,400000, 500000, 600000, 700000, 800000, 900000, 1000000, 2000000,3000000, 4000000, 5000000, 6000000, 7000000, 8000000, 9000000, 10000000,10⁸, 10⁹, or a number or a range between any two of these values. Insome embodiments, the number of microwells in the microarray can be atleast, or at most, 96, 384, 1536, 2000, 3000, 4000, 5000, 6000, 7000,8000, 9000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000,90000, 100000200000, 300000, 400000, 500000, 600000, 700000, 800000,900000, 1000000, 2000000, 3000000, 4000000, 5000000, 6000000, 7000000,8000000, 9000000, 10000000, 10⁸, 10⁹. In some embodiments, the number ofmicrowells in the microwell array can be about 96. In some embodiments,the number of microwells can be about 150000.

Microwell Array Surface Features

A microwell array can comprise surface features between the microwellsthat are designed to help guide cells and solid supports into the wellsand/or to prevent them from settling on the surfaces between wells.Non-limiting examples of suitable surface features include, but are notlimited to, domed, ridged, or peaked surface features that encircle thewells or straddle the surface between wells.

Substrate Fabrication Techniques

A microwell can be fabricated using any of a number of fabricationtechniques. Non-limiting examples of fabrication methods that can beused include bulk micromachining techniques such as photolithography andwet chemical etching, plasma etching, or deep reactive ion etching;micro-molding and micro-embossing; laser micromachining; 3D printing orother direct write fabrication processes using curable materials; andsimilar techniques.

Microwell arrays can be fabricated from a variety of substratematerials. The choice of material can depend on the choice offabrication technique, and vice versa. Non-limiting examples of suitablematerials include fused-silica, glass, polymers (e.g. agarose, gelatin,hydrogels, polydimethylsiloxane (PDMS) elastomer, polymethylmethacrylate(PMMA), polycarbonate (PC), polypropylene (PP), polyethylene (PE), highdensity polyethylene (HDPE), polyimide, cyclic olefin polymers (COP),cyclic olefin copolymers (COC), polyethylene terephthalate (PET), epoxyresins, thiol-ene based resins, metals or metal films (e.g. aluminum,stainless steel, copper, nickel, chromium, and titanium), and the like.A hydrophilic material can be desirable for fabrication of the microwellarrays (e.g. to enhance wettability and minimize non-specific binding ofcells and other biological material). Hydrophobic materials that can betreated or coated (e.g. by oxygen plasma treatment, or grafting of apolyethylene oxide surface layer) can be used for fabrication of themicrowell arrays. The use of porous, hydrophilic materials for thefabrication of the microwell array can be desirable in order tofacilitate capillary wicking/venting of entrapped gas or air bubbles inthe device. The microwell array can be fabricated from a singlematerial. The microwell array can comprise two or more differentmaterials that have been bonded together or mechanically joined.

Substrate Shapes and Sizes

A substrate can have variety of shapes and sizes. For example, the shape(or footprint) of the substrate within which microwells are fabricatedcan be square, rectangular, circular, or irregular in shape. The size ofcan be characterized by its width, length, and depth.

The width of a substrate can vary, ranging from 0.1 inch to 10 inches.In some embodiments, the width of the substrate can be, or be about,0.1, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9,10 inches, or a number or a range between any two of these values. Insome embodiments, the width of the substrate can be at least, or atmost, 0.1, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7,8, 9, or 10 inches. The width of the substrate can vary, ranging from0.2 centimeter to 20 centimeters. In some embodiments, the width of thesubstrate can be, or be about, 0.2, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8,0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20 centimeters, or a number or arange between any two of these values. In some embodiments, the width ofthe substrate can be at least, or at most, 0.2, 0.3, 0.4, 05, 0.6, 0.7,0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 20 centimeters.

The length of a substrate can vary, ranging from 0.1 inch to 10 inches.In some embodiments, the length of the substrate can be, or be about,0.1, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9,10 inches, or a number or a range between any two of these values. Insome embodiments, the length of the substrate can be at least, or atmost, 0.1, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7,8, 9, or 10 inches. The length of the substrate can vary, ranging from0.2 centimeter to 20 centimeters. In some embodiments, the length of thesubstrate can be, or be about, 0.2, 0.2, 0.3, 0.4, 05, 0.6, 0.7, 0.8,0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20 centimeters, or a number or arange between any two of these values. In some embodiments, the lengthof the substrate can be at least, or at most, 0.2, 0.3, 0.4, 05, 0.6,0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 20 centimeters.

In some embodiments, the footprint of a substrate, for example definedby its width and length, can be similar to that of a microtiter plate.In some embodiments, the footprint of the microwell array substrate canbe similar to that of standard microscope slides. Non-limiting examplesof the footprint of standard microscope slides include about 75 mmlong×25 mm wide (about 3″ long×about 1″ wide) and about 75 mm long×50 mmwide (about 3″ long×2″ wide).

The thickness of the substrate within which the microwells arefabricated can range from about 0.1 mm thick to about 10 mm thick, ormore. The thickness of the microwell array substrate can be, or beabout, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, or a number or arange between any two of these values. The thickness of the microwellarray substrate can be at least, or at most, 10, 9, 8, 7, 6, 5, 4, 3, 2,1, 0.5, 0.1 mm. The thickness of the microwell array substrate can beabout 1 mm thick. The thickness of the microwell array substrate can beany value within these ranges, for example, the thickness of themicrowell array substrate can be between about 0.2 mm and about 9.5 mm.

Microwell Array Surface Treatments

A variety of surface treatments and surface modification techniques canbe used to modify the properties of microwell array surfaces. Examplescan include, but are not limited to, oxygen plasma treatments to renderhydrophobic material surfaces more hydrophilic, the use of wet or dryetching techniques to smooth or roughen glass and silicon surfaces,adsorption or grafting of polyethylene oxide or other polymer layers,for example pluronic, or bovine serum albumin to substrate surfaces torender them more hydrophilic and less prone to non-specific adsorptionof biomolecules and cells, the use of silane reactions to graftchemically-reactive functional groups to otherwise inert silicon andglass surfaces, etc. Photodeprotection techniques can be used toselectively activate chemically-reactive functional groups at specificlocations in the array structure, for example, the selective addition oractivation of chemically-reactive functional groups such as primaryamines or carboxyl groups on the inner walls of the microwells can beused to covalently couple oligonucleotide probes, peptides, proteins, orother biomolecules to the walls of the microwells. The choice of surfacetreatment or surface modification utilized can depend on the type ofsurface property that is desired and/or on the type of material fromwhich the microwell array is made.

Microwell Sealing

The openings of microwells can be sealed, for example, during cell lysissteps to prevent cross hybridization of target nucleic acid betweenadjacent microwells. A microwell (or array of microwells) can be sealedor capped using, for example, a flexible membrane or sheet of solidmaterial (i.e. a plate or platten) that clamps against the surface ofthe microwell array substrate, or a suitable bead, where the diameter ofthe bead is larger than the diameter of the microwell.

A seal formed using a flexible membrane or sheet of solid material cancomprise, for example, inorganic nanopore membranes (e.g., aluminumoxides), dialysis membranes, glass slides, coverslips, elastomeric films(e.g. PDMS), or hydrophilic polymer films (e.g., a polymer film coatedwith a thin film of agarose that has been hydrated with lysis buffer).

Solid supports (e.g., beads) used for capping the microwells cancomprise any of the solid supports (e.g., beads) of the disclosure. Insome embodiments, the solid supports are cross-linked dextran beads(e.g., Sephadex). Cross-linked dextran can range from about 10micrometers to about 80 micrometers. In some embodiments, thecross-linked dextran beads used for capping can be, or be about, 10, 20,30, 40, 50, 60, 70, 80 micrometers, or a number or a range between anytwo of these values. In some embodiments, the cross-linked dextran beadsused for capping can be at least, or at most, 10, 20, 30, 40, 50, 60,70, or 80 micrometers. The beads can be larger than the diameters of themicrowells. In some embodiments, the beads can be, or be about, 10%,20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, or a number or a rangebetween any two of these values, larger than the diameter of themicrowells. In some embodiments, the beads can be at least, or at most,10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 99%, larger than thediameter of the microwells.

The seal or cap can allow buffer to pass into and out of the microwells,while preventing macromolecules (e.g., nucleic acids) from migrating outof the well. In some embodiments, a macromolecule of or of about 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, or a numberor a range between any two of these values, nucleotides can be blockedfrom migrating into or out of the microwell by the seal or cap. In someembodiments, a macromolecule of at least, or at most, 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nucleotides can beblocked from migrating into or out of the microwell by the seal or cap.

Solid Support Manipulation

Solid supports (e.g., synthetic particles or beads) can be distributedamong a substrate. Solid supports can be distributed among wells of thesubstrate, removed from the wells of the substrate, or otherwisetransported through a device comprising one or more microwell arrays bymeans of centrifugation or other non-magnetic means. A microwell of asubstrate can be pre-loaded with a solid support. A microwell of asubstrate can hold or can hold about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 solidsupports. A microwell of a substrate can hold at least, or at most, 1,2, 3, 4, 5, 6, 7, 8, 9, 10 solid supports. In some embodiments, amicrowell of a substrate can hold one solid support.

Consumables

Microwell arrays can be a consumable component of the assay system.Microwell arrays can be reusable. Microwell arrays can be configured foruse as a stand-alone device for performing assays manually, or they canbe configured to comprise a fixed or removable component of aninstrument system that provides for full or partial automation of theassay procedure. In some embodiments of the disclosed methods, thebead-based libraries of stochastic barcodes can be deposited in thewells of the microwell array as part of the assay procedure. In someembodiments, the beads can be pre-loaded into the wells of the microwellarray and provided to the user as part of, for example, a kit forperforming stochastic barcoding and digital counting of nucleic acidtargets.

Two Mated Microwell Arrays

In some embodiments, two mated microwell arrays can be provided, onepre-loaded with beads which are held in place by a first magnet, and theother for use by the user in loading individual cells. Followingdistribution of cells into the second microwell array, the two arrayscan be placed face-to-face and the first magnet removed while a secondmagnet is used to draw the beads from the first array down into thecorresponding microwells of the second array, thereby ensuring that thebeads rest above the cells in the second microwell array and thusminimizing diffusional loss of target molecules following cell lysis,while maximizing efficient attachment of target molecules to thestochastic barcodes on the bead.

Substrates without Microwells

In some embodiments, a substrate does not include microwells. Forexample, beads can be assembled. For example, beads can beself-assembled. The beads can self-assemble into a monolayer. Themonolayer can be on a flat surface of the substrate. The monolayer canbe on a curved surface of the substrate. The bead monolayer can beformed by any method, such as alcohol evaporation.

Individual cells and beads can be compartmentalized using alternativesto microwells, for example, a single solid support and a single cellcould be confined within a single droplet in an emulsion (e.g. in adroplet digital microfluidic system).

Cells could be confined within porous beads that themselves comprise theplurality of tethered stochastic barcodes. Individual cells and solidsupports can be compartmentalized in any type of container,microcontainer, reaction chamber, reaction vessel, or the like.

Single cell, stochastic barcoding can be performed without the use ofmicrowells. Single cell, stochastic barcoding assays can be performedwithout the use of any physical container. For example, stochasticbarcoding without a physical container can be performed by embeddingcells and beads in close proximity to each other within a polymer layeror gel layer to create a diffusional barrier between different cell/beadpairs. For example, stochastic barcoding without a physical containercan be performed in situ, in vivo, on an intact solid tissue, on anintact cell, and/or subcellularly.

Methods of Stochastic Barcoding

Provided herein are methods for estimating the number of distincttargets at distinct locations in a physical sample (e.g., tissue, organ,tumor, cell). The methods can comprise placing the stochastic barcodesin close proximity with the sample, lysing the sample, associatingdistinct targets with the stochastic barcodes, amplifying the targetsand/or digitally counting the targets. The method can further compriseanalyzing and/or visualizing the information obtained from the spatiallabels on the stochastic barcodes. In some embodiments, the methodcomprises visualizing the plurality of targets in the sample. Mappingthe plurality of targets onto the map of the sample can includegenerating a two dimensional map or a three dimensional map of thesample. The two dimensional map and the three dimensional map can begenerated prior to or after stochastically barcoding the plurality oftargets in the sample. Visualizing the plurality of targets in thesample can include mapping the plurality of targets onto a map of thesample. Mapping the plurality of targets onto the map of the sample caninclude generating a two dimensional map or a three dimensional map ofthe sample. The two dimensional map and the three dimensional map can begenerated prior to or after stochastically barcoding the plurality oftargets in the sample. in some embodiments, the two dimensional map andthe three dimensional map can be generated before or after lysing thesample. Lysing the sample before or after generating the two dimensionalmap or the three dimensional map can include heating the sample,contacting the sample with a detergent, changing the pH of the sample,or any combination thereof.

In some embodiments, stochastically barcoding the plurality of targetscomprises hybridizing a plurality of stochastic barcodes with aplurality of targets to create stochastically barcoded targets.Stochastically barcoding the plurality of targets can comprisegenerating an indexed library of the stochastically barcoded targets.Generating an indexed library of the stochastically barcoded targets canbe performed with a solid support comprising the plurality of stochasticbarcodes.

Contacting a Sample and Stochastic Barcode(s)

The disclosure provides for methods for contacting a sample (e.g.,cells) to a substrate of the disclosure. A sample comprising, forexample, a cell, organ, or tissue thin section, can be contacted tostochastic barcodes. The cells can be contacted, for example, by gravityflow wherein the cells can settle and create a monolayer. The sample canbe a tissue thin section. The thin section can be placed on thesubstrate. The sample can be one-dimensional (e.g., form a planarsurface). The sample (e.g., cells) can be spread across the substrate,for example, by growing/culturing the cells on the substrate.

When stochastic barcodes are in close proximity to targets, the targetscan hybridize to the stochastic barcode. The stochastic barcodes can becontacted at a non-depletable ratio such that each distinct target canassociate with a distinct stochastic barcode of the disclosure. Toensure efficient association between the target and the stochasticbarcode, the targets can be crosslinked to the stochastic barcode.

Cell Lysis

Following the distribution of cells and stochastic barcodes, the cellscan be lysed to liberate the target molecules. Cell lysis can beaccomplished by any of a variety of means, for example, by chemical orbiochemical means, by osmotic shock, or by means of thermal lysis,mechanical lysis, or optical lysis. Cells can be lysed by addition of acell lysis buffer comprising a detergent (e.g. SDS, Li dodecyl sulfate,Triton X-100, Tween-20, or NP-40), an organic solvent (e.g. methanol oracetone), or digestive enzymes (e.g. proteinase K, pepsin, or trypsin),or any combination thereof. To increase the association of a target anda stochastic barcode, the rate of the diffusion of the target moleculescan be altered by for example, reducing the temperature and/orincreasing the viscosity of the lysate.

In some embodiments, the sample can be lysed using a filter paper. Thefilter paper can be soaked with a lysis buffer on top of the filterpaper. The filter paper can be applied to the sample with pressure whichcan facilitate lysis of the sample and hybridization of the targets ofthe sample to the substrate.

In some embodiments, lysis can be performed by mechanical lysis, heatlysis, optical lysis, and/or chemical lysis. Chemical lysis can includethe use of digestive enzymes such as proteinase K, pepsin, and trypsin.Lysis can be performed by the addition of a lysis buffer to thesubstrate. A lysis buffer can comprise Tris HCl. A lysis buffer cancomprise at least about 0.01, 0.05, 0.1, 0.5, or 1 M or more Tris HCl. Alysis buffer can comprise at most about 0.01, 0.05, 0.1, 0.5, or 1 M ormore Tris HCL. A lysis buffer can comprise about 0.1 M Tris HCl. The pHof the lysis buffer can be at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, or10 or more. The pH of the lysis buffer can be at most about 1, 2, 3, 4,5, 6, 7, 8, 9, or 10 or more. In some embodiments, the pH of the lysisbuffer is about 7.5. The lysis buffer can comprise a salt (e.g., LiCl).The concentration of salt in the lysis buffer can be at least about 0.1,0.5, or 1 M or more. The concentration of salt in the lysis buffer canbe at most about 0.1, 0.5, or 1 M or more. In some embodiments, theconcentration of salt in the lysis buffer is about 0.5M. The lysisbuffer can comprise a detergent (e.g., SDS, Li dodecyl sulfate, tritonX, tween, NP-40). The concentration of the detergent in the lysis buffercan be at least about 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%,0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, or 7% or more. The concentration ofthe detergent in the lysis buffer can be at most about 0.0001%, 0.0005%,0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, or 7%or more. In some embodiments, the concentration of the detergent in thelysis buffer is about 1% Li dodecyl sulfate. The time used in the methodfor lysis can be dependent on the amount of detergent used. In someembodiments, the more detergent used, the less time needed for lysis.The lysis buffer can comprise a chelating agent (e.g., EDTA, EGTA). Theconcentration of a chelating agent in the lysis buffer can be at leastabout 1, 5, 10, 15, 20, 25, or 30 mM or more. The concentration of achelating agent in the lysis buffer can be at most about 1, 5, 10, 15,20, 25, or 30 mM or more. In some embodiments, the concentration ofchelating agent in the lysis buffer is about 10 mM. The lysis buffer cancomprise a reducing reagent (e.g., beta-mercaptoethanol, DTT). Theconcentration of the reducing reagent in the lysis buffer can be atleast about 1, 5, 10, 15, or 20 mM or more. The concentration of thereducing reagent in the lysis buffer can be at most about 1, 5, 10, 15,or 20 mM or more. In some embodiments, the concentration of reducingreagent in the lysis buffer is about 5 mM. In some embodiments, a lysisbuffer can comprise about 0.1M TrisHCl, about pH 7.5, about 0.5M LiCl,about 1% lithium dodecyl sulfate, about 10 mM EDTA, and about 5 mM DTT.

Lysis can be performed at a temperature of about 4, 10, 15, 20, 25, or30° C. Lysis can be performed for about 1, 5, 10, 15, or 20 or moreminutes. A lysed cell can comprise at least about 100000, 200000,300000, 400000, 500000, 600000, or 700000 or more target nucleic acidmolecules. A lysed cell can comprise at most about 100000, 200000,300000, 400000, 500000, 600000, or 700000 or more target nucleic acidmolecules.

Attachment of Stochastic Barcodes to Target Nucleic Acid Molecules

Following lysis of the cells and release of nucleic acid moleculestherefrom, the nucleic acid molecules can randomly associate with thestochastic barcodes of the co-localized solid support. Association cancomprise hybridization of a stochastic barcode's target recognitionregion to a complementary portion of the target nucleic acid molecule(e.g., oligo(dT) of the stochastic barcode can interact with a poly(A)tail of a target). The assay conditions used for hybridization (e.g.buffer pH, ionic strength, temperature, etc.) can be chosen to promoteformation of specific, stable hybrids. In some embodiments, the nucleicacid molecules released from the lysed cells can associate with theplurality of probes on the substrate (e.g., hybridize with the probes onthe substrate). When the probes comprise oligo(dT), mRNA molecules canhybridize to the probes and be reverse transcribed. The oligo(dT)portion of the oligonucleotide can act as a primer for first strandsynthesis of the cDNA molecule. For example, mRNA molecules canhybridize to stochastic barcodes on beads. For example, single-strandednucleotide fragments can hybridize to the target-binding regions ofstochastic barcodes.

Attachment can further comprise ligation of a stochastic barcode'starget recognition region and a portion of the target nucleic acidmolecule. For example, the target binding region can comprise a nucleicacid sequence that can be capable of specific hybridization to arestriction site overhang (e.g. an EcoRI sticky-end overhang). The assayprocedure can further comprise treating the target nucleic acids with arestriction enzyme (e.g. EcoRI) to create a restriction site overhang.The stochastic barcode can then be ligated to any nucleic acid moleculecomprising a sequence complementary to the restriction site overhang. Aligase (e.g., T4 DNA ligase) can be used to join the two fragments.

For example, the labeled targets from a plurality of cells (or aplurality of samples) (e.g., target-barcode molecules) can besubsequently pooled, for example, into a tube. The labeled targets canbe pooled by, for example, retrieving the stochastic barcodes and/or thebeads to which the target-barcode molecules are attached.

The retrieval of solid support-based collections of attachedtarget-barcode molecules can be implemented by use of magnetic beads andan externally-applied magnetic field. Once the target-barcode moleculeshave been pooled, all further processing can proceed in a singlereaction vessel. Further processing can include, for example, reversetranscription reactions, amplification reactions, cleavage reactions,dissociation reactions, and/or nucleic acid extension reactions. Furtherprocessing reactions can be performed within the microwells, that is,without first pooling the labeled target nucleic acid molecules from aplurality of cells.

Loading Station

The disclosure provides for loading stations for facilitatingperformance of one or more workflow procedures using a flowcell and/ormicrowell array. For example, the loading systems described herein canbe used to facilitate stochastic barcoding.

A non-limiting embodiment of a loading station 100 is illustrated inFIG. 1. The loading station 100 can include one or more structures orfeatures designed to facilitate performance of a workflow. In someembodiments, a workflow can include a series of steps for hybridizinggenetic information from a plurality of cells onto a plurality ofbarcode-bearing beads. For example, in some embodiments, a workflow caninclude steps of introducing a plurality of cells into a microcellarray, introducing a plurality of barcode-bearing beads into themicrowell array, lysing the plurality of cells so that geneticinformation from the cells hybridizes with the plurality of beads,and/or collecting the beads from the microwell array.

As described herein, the microwell array for use with the flowcell 100can include one or more microwells. Each microwell can be configured toreceive one or more particles, such as barcode-bearing beads and/orcells. In some embodiments, the microwell array can be packaged within aflowcell that provides for convenient interfacing with the loadingstation 100 and facilitates the exchange of fluids, e.g. cell and solidsupport suspensions, lysis buffers, rinse buffers, etc., that aredelivered to the microwell array. In some embodiments, the microwellarray and the flowcell can be packaged within a consumable cartridgethat provides for convenient interfacing with loading station 100.

As shown in FIG. 1, the loading station 100 includes a body 105 and atray 110. The tray 110 can be positioned on a superior surface of thebody 105. In some embodiments, the tray 110 can receive a microwellarray, flowcell, and/or cartridge within the loading station 100. Insome embodiments, the tray 110 can be dimensioned, positioned, orotherwise configured to orient a microwell array, flowcell, and/orcartridge in a predefined position within the loading station 100. Thepredefined position can facilitate the interaction of other features ofthe loading station 100 with the microwell array, flowcell, and/orcartridge. In some embodiments, the tray 110 can releasably secure themicrowell array, flowcell, and/or cartridge within the loading station100. Securing the microwell array, flowcell, and/or cartridge within theloading station 100 can prevent misalignment of the microwell array,flowcell, and/or cartridge with other features of the loading station100 while a workflow is performed using the loading station 100.

In some embodiments, the loading station 100 can include a magnet 120.The magnet 120 can be positioned adjacent to the tray 110. In someembodiments, the magnet 120 can be positioned inferior to at least aportion of the tray 110 and/or the microwell array when positionedwithin the loading station 100. In some embodiments, the tray 110 caninclude a cover 114 positioned between the magnet 120 and a location ofthe tray 110 for receiving the microwell array, flowcell, and/orcartridge. In such embodiments, the cover 114 can restrict spillover orother contamination from the microwell array, flowcell, and/or cartridgefrom reaching the magnet 120. In some embodiments, the magnet 120 can bepositioned within the body 105 of the loading station 100. In someembodiments, the magnet 120 can be configured to produce a magneticfield to attract one or more particles within the microwell array. Forexample, in some embodiments, one or more barcode-bearing beads can bemagnetic or can have a magnetic material affixed thereon. In someembodiments, the magnet 120 can be configured to attract thebarcode-bearing beads.

In some embodiments, the magnet 120 can be movable relative to the tray110 and/or microwell array when positioned within the tray 110. Forexample, in some embodiments the magnet 120 can be movable between afirst position or inactive position in which a magnetic field producedby the magnet 120 does not attract magnetic particles within themicrowell array or exerts a relatively weak attractive force on magneticparticles positioned within the microwell array when the microwell arrayis positioned within the tray 110 and a second position or activeposition in which the magnetic field produced by the magnet 120 canattract magnetic particles within the microwell array when the microwellarray is positioned within the tray 110.

When in the active position a superior surface of the magnet 120 can bein parallel with an inferior surface of the flowcell and/or cartridge.In some embodiments, the superior surface of the magnet 120 can be 1.0mm away or approximately 1.0 mm away from the inferior surface of theflowcell and/or cartridge when in the active position. In someembodiments, the superior surface of the magnet 120 can be 0.5 mm, 1.5mm, 2.0 mm, 2.5 mm, 3.0 mm, less than 0.5 mm, less than 1.0 mm, no morethan 1.0 mm, less than 1.5 mm, less than 2.0 mm, less than 2.5 mm, lessthan 3.0 mm, or between 0.5 mm and 1.5 mm away from the inferior surfaceof the flowcell and/or cartridge when the magnet 120 is in the activeposition. In some embodiments, the superior surface of the magnet 120can be sized and shaped to extend to or beyond the boundaries of anactive area of the flowcell.

In some embodiments, in the inactive position, at least a portion of themagnet 120 is positioned at a further distance from the microwell arrayin at least one direction in comparison to the active position. Themagnet 120 is shown in the inactive position in FIG. 1.

Although two positions of the magnet 120 are described with respect toFIG. 1, it should be recognized that in certain embodiments, the magnet120 can move over more than two positions. In some embodiments, themagnet 120 can move between discrete positions. In some embodiments, themagnet 120 can move over a continuous range of positions. Differentpositions of the magnet 120 can allow for the application of differentamounts of magnetic force on magnetic particles within the microarraywhen the microarray is positioned within the tray 110.

In some embodiments, the loading station 100 can include a magnet 130.The magnet 130 can be positioned adjacent to the tray 110. In someembodiments, the magnet 130 can be positioned superior to at least aportion of the tray 110 and/or the microwell array when positionedwithin the loading station 100. In some embodiments, the magnet 130 canbe positioned within a portion of the body 105. In some embodiments, themagnet 130 can be configured to produce a magnetic field to attract oneor more particles within the microwell array, such as, for example, thebarcode-bearing beads.

In some embodiments the magnet 130 can be movable between a firstposition or inactive position in which a magnetic field produced by themagnet 130 does not attract magnetic particles within the microwellarray or exerts a relatively weak attractive force on magnetic particlespositioned within the microwell array when the microwell array ispositioned within the tray 110 and a second position or active positionin which the magnetic field produced by the magnet 130 can attractmagnetic particles within the microwell array when the microwell arrayis positioned within the tray 110.

When in the active position an inferior surface of the magnet 130 can bein parallel with a superior surface of the flowcell and/or cartridge. Insome embodiments, the inferior surface of the magnet 130 can be 1.0 mmaway or approximately 1.0 mm away from the superior surface of theflowcell and/or cartridge when in the active position. In someembodiments, the inferior surface of the magnet 130 can be 0.5 mm, 1.5mm, 2.0 mm, 2.5 mm, 3.0 mm, less than 0.5 mm, less than 1.0 mm, no morethan 1.0 mm, less than 1.5 mm, less than 2.0 mm, less than 2.5 mm, lessthan 3.0 mm, or between 0.5 mm and 1.5 mm away from the superior surfaceof the flowcell and/or cartridge when the magnet 130 is in the activeposition. In some embodiments, the inferior surface of the magnet 130can be sized and shaped to extend to or beyond the boundaries of theactive area of the flowcell.

The magnet 130 is shown in the inactive position in FIG. 1. In someembodiments, the magnet 130 is positioned within the body 105 of theloading station 100 when in the first position. In some embodiments, themagnet 130 extends out of an opening 107 in the housing 105 whentransitioning to the active position.

Although two positions of the magnet 130 are described with respect toFIG. 1, it should be recognized that in certain embodiments, the magnet130 can move over more than two positions. In some embodiments, themagnet 130 can move between discrete positions. In some embodiments, themagnet 130 can move over a continuous range of positions. Differentpositions of the magnet 130 can allow for the application of differentamounts of magnetic force on magnetic particles within the microarraywhen the microarray is positioned within the tray 110.

In some embodiments, the loading station 100 can include an actuator140. In some embodiments, the actuator 140 can be actuated to transitionthe magnet 120 between the inactive position and the active position. Insome embodiments, the actuator 140 can be actuated to transition themagnet 130 between the inactive position and the active position. Insome embodiments, the actuator 120 can be actuated to move either themagnet 120 or the magnet 130 between their respective inactive positionsand active positions. In some embodiments, the actuator 140 can beactuated to move both the magnet 120 and the magnet 130 between theirrespective inactive positions and active positions.

In some embodiments, the loading station 100 can be configured toprevent both the magnet 120 and magnet 130 from being positioned withintheir respective active positions at the same time. For example, in someembodiments, the magnet 120 and magnet 130 are mechanically coupled suchthat movement of the magnet 120 to its active position causes movementof the magnet 130 to its inactive position. In some embodiments,movement of the magnet 130 to its active position causes movement of themagnet 120 to its inactive position. In some embodiments, both themagnet 120 and the magnet 130 can be mechanically coupled to theactuator 140 such that movement of the actuator 140 in a direction thatcauses the magnet 120 to transition to its active position results inmovement of the magnet 130 from its active position to its inactiveposition or results in maintenance of the magnet 130 in its inactiveposition. In some embodiments, movement of the actuator in a directionthat causes the magnet 130 to transition to its active position resultsin movement of the magnet 120 from its active position to its inactiveposition or results in maintenance of the magnet 120 in its inactiveposition. In some embodiments, the actuator 140 can be part of anactuation mechanism in which the actuator 140 is configured to engageone more actuation components mechanically coupled to the magnet 120 incertain positions and one or more actuation components mechanicallycoupled to the magnet 130 in other positions.

In some embodiments, the actuator 140 can be moved between threepositions, a first position, a second position, and a third position. Insome embodiments, when the actuator is in the first position, both themagnet 120 and the magnet 130 are in their respective inactivepositions. The first position of the actuator can be referred to as a“neutral” position. In some embodiments, transitioning the actuator 140to its second position can cause the magnet 120 to transition to itsactive position. The second position of the actuator can be referred toas a “lysis” position. As described further herein, in certainembodiments, positioning the magnet 120 in its active position canfacilitate lysis of cells within the microwell array when the microwellarray is positioned within the tray 110. In some embodiments, theactuator 140 is mechanically coupled to the magnet 120 and 130 such thatthe magnet 130 is positioned within its inactive position when theactuator is in the second position. In some embodiments, transitioningthe actuator 140 to its third position can cause the magnet 130 totransition to its active position. The third position of the actuatorcan be referred to as a “retrieval” position. As described furtherherein, in certain embodiments, positioning the magnet 130 in its activeposition can facilitate retrieval of barcode-bearing beads positionedwithin the microwell array when the microwell array is positioned withinthe tray 110.

Although three positions of the actuator 140 are described with respectto FIG. 1, it should be recognized that in certain embodiments, theactuator 140 can move between two positions or between more than twopositions. In some embodiments, the actuator 140 can move betweendiscrete positions. In some embodiments, the actuator 140 can move overa continuous range of positions.

As shown in FIG. 1, the actuator 140 can be a sliding actuatorconfigured to slide along a track. In some embodiments, the actuator 140can be a lever, a button, a switch, or any other suitable actuator.

In some embodiments, the loading station 100 can include drawer 150. Insome embodiments, the drawer 150 can include a receptacle 156. Thereceptacle 156 can be configured to receive one or more tubes. FIG. 1depicts a first tube 152 a and a second tube 152 b positioned within thetube receptacle 156 of the drawer 150. In some embodiments, the tubes152 a and 152 b are Eppendorf tubes. In some embodiments, the tubes 152a and 152 b are 5 ml Eppendorf tubes.

In some embodiments, the drawer 150 can position the tubes 152 a and 152b within the loading station 100. For example, the drawer 150 can alignat least one of the tubes 152 a and 152 b with an outlet of the flowcellcontaining the microwell array.

In some embodiments, the drawer 150 is movable within the load cell 100.In some embodiments, the drawer 150 is movable to a first position, inwhich a portion of the drawer 150 is positioned outside of the body 105.In some embodiments, the first position can be a loading position. Whenin the loading position, tubes 152 a and 152 b can be received by thereceptacle 156 of the drawer 150 and/or removed from the drawer 150.

In some embodiments, the drawer 150 is movable to a second position. Inthe second position, the drawer 150 can be positioned within the body105. In some embodiments, one of the tubes 152 a and 152 b are alignedwith the outlet of the flowcell when the drawer 150 is in the secondposition. In some embodiments, the second position is a waste collectionposition, in which one of the tubes 152 a and 152 b designated for wastecollection is aligned with the outlet of the flowcell.

In some embodiments, the drawer 150 is moveable to a third position. Inthe third position, the drawer 150 can be positioned within the body105. In some embodiments, the one of the tubes 152 a and 152 b that doesnot align with the outlet of the flowcell in the second position can bealigned with the outlet of the flowcell in the third position. In someembodiments, the third position is a bead collection position, in whichone of the tubes 152 a and 152 b designated for bead collection isaligned with the outlet of the flowcell.

In some embodiments, the drawer 150 can be movable along a guiderail. Insome embodiments, the guiderail should be positioned to engage a topsurface of the drawer 150 or side surface of the drawer 150 in use. Insome embodiments, the guiderail should be positioned to reduce contactfrom spilling or splashing liquids within the collection tubes 152 a and152 b. In some embodiments, the drawer 150 can be positioned within aseparate compartment of the body 105 from the magnet 120 and/or themagnet 130 to prevent contact from spilling or splashing liquids withinthe collection tubes. In some embodiments, the drawer 150 can bepositioned such that motion of the drawer 150 does not interfere withmotion of the magnet 120.

In some embodiments, the loading station 100 can include an actuator160. In some embodiments, the actuator 160 can be mechanically coupledto the drawer 150. In some embodiments, the actuator 160 can be actuatedto transition the drawer 150 between the first position, the secondposition, and/or the third position of the drawer 150 by movement of theactuator 160 between a first position, a second position, and a thirdposition, respectively.

Although three positions of the actuator 160 are described with respectto FIG. 1, it should be recognized that in certain embodiments, theactuator 160 can move between two positions or between more than twopositions. In some embodiments, the actuator 160 can move betweendiscrete positions. In some embodiments, the actuator 160 can move overa continuous range of positions.

As shown in FIG. 1, the actuator 160 can be a sliding actuatorconfigured to slide along a track. In some embodiments, the actuator 160can be a lever, a button, a switch, or any other suitable actuator.

As described herein, the body 105 can provide a housing for variouscomponents of the loading station 100. In some embodiments, the body 105can provide a housing to prevent damage to components of the loadingsystem, such as the magnet 120 and the magnet 130. In some embodiments,the body 105 can house the magnets 120 and 130 in order to preventmagnetic attraction of external bodies.

In some embodiments, the loading station 100 can be dimensioned so thatthe loading station 100 can be portable. In some embodiments, theloading station 100 can be light weight. In some embodiments, componentsof the loading station can be formed of materials that facilitatesterilization using alcohol wipes and/or bleach. In some embodiments,components of the loading station can be formed of materials thatfacilitate sterilization using alcohol wipes and 10% bleach.

Although the embodiment of the loading station 100 shown in FIG. 1includes two magnets, in certain embodiments, the loading station 100may include only a single magnet configured to move over a range ofpositions. For example, in some embodiments, the single magnet can bemovable to the active position of the magnet 120 for certain steps in aworkflow performed using the loading station 100. In some embodiments,the single magnet can be movable to the active position of magnet 130during other steps in the workflow performed using the loading station100. In certain embodiments, the single magnet can be moved to one ormore other positions in which the single magnet does not exert a forceor exerts a relatively weak force on the beads during other steps in theworkflow performed using the loading station 100, such as, for example,the inactive position of the magnet 120 and/or the inactive position ofthe magnet 130.

In some embodiments, the loading station 100 can have more than twomagnets. In some embodiments, each magnet can have a separate actuatorfor transitioning between its inactive position and active position.

Flowcell

As discussed herein, in some embodiments, the microwell array can bepositioned within a flowcell to facilitate interfacing with the loadingstation 100. Design features can include: (i) one or more inlet portsfor introducing cell samples, solid support suspensions, or other assayreagents, (ii) one or more microwell array chambers designed to providefor efficient (e.g., uniform) filling and fluid-exchange whileminimizing back eddies or dead zones, and (iii) one or more outlet portsfor delivery of fluids to a sample collection point or a wastereservoir.

The design of the flowcell can include a plurality of microarraychambers that interface with a plurality of microwell arrays such thatone or more different cell samples can be processed in parallel. Thedesign of the flowcell can further include features for creatingconsistent (e.g., uniform) flow velocity profiles, i.e. “plug flow”,across the width of the array chamber to provide for more efficient(e.g., uniform) delivery of cells and beads to the microwells, forexample, by using a porous barrier located near the chamber inlet andupstream of the microwell array as a “flow diffuser”, or by dividingeach array chamber into several subsections that collectively cover thesame total array area, but through which the divided inlet fluid streamflows in parallel. In some embodiments, the flowcell can enclose orincorporate more than one microwell array substrate. In someembodiments, the integrated microwell array/flowcell assembly canconstitute a fixed component of the system. In some embodiments, themicrowell array/flowcell assembly can be removable from the instrument.

In general, the dimensions of fluidic channel(s) and the arraychamber(s) in flowcell designs will be optimized to (i) provideefficient (e.g., uniform) delivery of cells and beads to the microwellarray, and (ii) to minimize sample and reagent consumption. The width ofa fluidic channel can be different in different implementations, forexample, ranging from 0.1 mm to 100 mm. In some embodiments, the widthcan be, or be about, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 mm, or anumber or a range between any two of these values. In some embodiments,the width can be at least, or at most, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70,80, 90, or 100 mm.

The height of a fluidic channel can be different in differentimplementations, for example, ranging from 0.1 mm to 100 mm. In someembodiments, the height can be, or be about, 0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2,3, 4, 5, 6, 7, 8, 9, 10 mm, or a number or a range between any two ofthese values. In some embodiments, the height can be at least, or atmost, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3,1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm.

Flowcells can be fabricated using a variety of techniques and materialsknown to those of skill in the art. In general, a flowcell can befabricated as a separate part and subsequently either mechanicallyclamped or permanently bonded to the microwell array substrate. Examplesof suitable fabrication techniques include conventional machining, CNCmachining, injection molding, 3D printing, alignment and lamination ofone or more layers of laser or die-cut polymer films, or any of a numberof microfabrication techniques such as photolithography and wet chemicaletching, dry etching, deep reactive ion etching, or lasermicromachining.

Once the flowcell part has been fabricated it can be attached to themicrowell array substrate mechanically, e.g. by clamping it against themicrowell array substrate (with or without the use of a gasket), or itcan be bonded directly to the microwell array substrate using any of avariety of techniques (depending on the choice of materials used) knownto those of skill in the art, for example, through the use of anodicbonding, thermal bonding, or any of a variety of adhesives or adhesivefilms, including epoxy-based, acrylic-based, silicone-based, UV curable,polyurethane-based, or cyanoacrylate-based adhesives. In someembodiments, the substrate can form the fluidic channel bottom of thefluidic channel, or the substrate can be on the fluidic channel bottomof the fluidic channel. In some embodiments, the substrate comprisessilicon, fused-silica, glass, a polymer, a metal, an elastomer,polydimethylsiloxane, agarose, a hydrogel, or a combination thereof.

Flowcells can be fabricated using a variety of materials known to thoseof skill in the art. In general, the choice of material used will dependon the choice of fabrication technique used, and vice versa. Examples ofsuitable materials include, but are not limited to, silicon,fused-silica, glass, any of a variety of polymers, e.g.polydimethylsiloxane (PDMS; elastomer), polymethylmethacrylate (PMMA),polycarbonate (PC), polypropylene (PP), polyethylene (PE), high densitypolyethylene (HDPE), polyimide, cyclic olefin polymers (COP), cyclicolefin copolymers (COC), polyethylene terephthalate (PET), epoxy resins,metals (e.g. aluminum, stainless steel, copper, nickel, chromium, andtitanium), a non-stick material such as teflon (PTFE), or a combinationof these materials. The cyclic olefin polymers (COP) can comprise Zeonor1020R or Zeonor 1060R.

Cartridge

As described herein, the microwell array and the flowcell, can bepackaged within a consumable cartridge that provides for convenientinterfacing with the rest of the loading station 100. The flowcell canfacilitate the exchange of fluids, e.g. cell and bead suspensions, lysisbuffers, rinse buffers, etc., that are delivered to the microwells. Insome embodiments, the flow cell may be designed to facilitate efficient(e.g., uniform) distribution of cells and beads across the plurality ofmicrowells. Design features may include: (i) one or more inlet ports forintroducing cell samples, bead suspensions, or other assay reagents,(ii) one or more microwell chambers designed to provide for efficient(e.g., uniform) filling and efficient fluid-exchange while minimizingback eddies or dead zones, and (iii) one or more outlet ports fordelivery of fluids to a sample collection point or a waste reservoir. Insome embodiments, the design of the flow cell may include a plurality ofmicrowell chambers that interface with a plurality of microwell arrayson a single substrate, or with a plurality of microwell arraysubstrates, such that one or more different cell samples may beprocessed in parallel. In some embodiments, the design of the flow cell,e.g. the layout of the fluid channels and chambers, may be adjusted sothat different patterns of microwells (i.e. configurable microarraypatterns) are accessed by fluids in a given design.

FIG. 2 shows an exploded view of an embodiment of a cartridge 200 thatcan be used with the loading station 100. The cartridge 200 can includea flowcell 202 with a fluidic channel 204 formed by a microwell arraysubstrate 208, a fluid channel layer 212, and a cover plate 216. Thenumber of layers forming the flowcell 200 can be different in differentimplementations, ranging from 1 to 20. In some embodiments, the numberof layers forming the flowcell 200 can be, or be about, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or a number or arange between any two of these values. In some embodiments, the numberof layers forming the flowcell 200 can be at least, or at most, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

As shown in FIG. 2, the cartridge 200 can include an inlet port, formedby inlet port components 220 a and 220 b on the cover plate 216 and thefluidic channel layer 212 respectively. The inlet port components 220 aand 220 b can be coaxial along the axis 222. The cartridge 200 includesone outlet port 224 on the fluidic channel layer 212. The locations ofthe outlet port can be different in different implementations. In someembodiments, the outlet port can be on the cover plate 216. In someembodiments, the outlet port can be formed by outlet port components onthe cover plate 216 and the fluidic channel layer 212.

The cartridge 200 or the flowcell 202 can include (i) one or more inletports for creating fluid connections with the instrument or manuallyintroducing cell samples, bead suspensions, or other assay reagents intothe cartridge. The flowcell can include one or more of (ii) one or morebypass channels, i.e. for self-metering of cell samples and beadsuspensions, to avoid overfilling or back flow, (iii) one or moreintegrated microwell array/flowcell assemblies, or one or more chamberswithin which the microarray substrate(s) are positioned, (iv) integratedminiature pumps or other fluid actuation mechanisms for controllingfluid flow through the device, (v) integrated miniature valves (or othercontainment mechanisms) for compartmentalizing pre-loaded reagents (forexample, bead suspensions) or controlling fluid flow through the device,(vi) one or more vents for providing an escape path for trapped gas,(vii) one or more sample and reagent waste reservoirs, (viii) one ormore outlet ports for creating fluid connections with the instrument orproviding a processed sample collection point. (ix) mechanical interfacefeatures for reproducibly positioning the removable, consumablecartridge with respect to the instrument system, and for providingaccess so that external magnets can be brought into close proximity withthe microwell array, (x) integrated temperature control components or athermal interface for providing good thermal contact with the instrumentsystem, (xi) optical interface features, e.g. a transparent window, foruse in optical interrogation of the microwell array, or any combinationthereof.

FIG. 3 shows a cross-sectional view of the cartridge 200 taken along theplane 228 in FIG. 2. FIG. 3 shows two fluidic channel sections 204 a and204 b of the fluidic channel 204. The fluidic channel section 204 acomprises a fluidic channel ceiling 232, two fluidic channel sidewalls236 a and 236 b (also referred to as a first sidewall 236 a and a secondsidewall 236 b), and a fluidic channel bottom 240. The fluidic channelceiling 232 and the fluidic channel sidewall 236 a form an edge 244 a(also referred to as a ceiling-first sidewall edge). The fluidic channelceiling 232 and the fluidic channel sidewall 236 b form another edge 244b (also referred to as a ceiling-second sidewall edge). The fluidicchannel sidewalls 236 a and 236 b can have positive draft angles withrespect to the fluidic channel ceiling 232, for example, ranging from1-15 degrees. In some embodiments, the draft angle of the fluidicchannel sidewall 236 a or 236 b with respect to the fluidic channelceiling 232 can be, or be about, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15 degrees, or a number or a range between any two of thesevalues. In some embodiments, the draft angle of the fluidic channelsidewall 236 a or 236 b with respect to the fluidic channel ceiling 232can be at least, or at most, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, or 15 degrees.

The fluidic channel bottom 240 and the fluidic channel sidewall 236 aform an edge 248 a (also referred to as a bottom-first sidewall edge).The fluidic channel bottom 240 and the fluidic channel sidewall 236 bform another edge 248 b (also referred to as a bottom-second sidewalledge). The fluidic channel sidewalls 236 a and 236 b can have negativedraft angles with respect to the fluidic channel bottom 240, forexample, ranging from −1 to −15 degrees. In some embodiments, the draftangle of the fluidic channel sidewall 236 a or 236 b with respect to thefluidic channel bottom 240 can be, or be about, −1, −2, −3, −4, −5, −6,−7, −8, −9, −10, −11, −12, −13, −14, −15 degrees, or a number or a rangebetween any two of these values. In some embodiments, the draft angle ofthe fluidic channel sidewall 236 a or 236 b with respect to the fluidicchannel bottom 240 can be at least, or at most, −1, −2, −3, −4, −5, −6,−7, −8, −9, −10, −11, −12, −13, −14, or −15 degrees.

FIG. 4 shows a cross-sectional view of an exemplary fluidic channel 204of a cartridge 200. The fluidic channel 204 comprises a fluidic channelceiling 232, two fluidic channel sidewalls 236 a and 236 b, and afluidic channel bottom 240. The fluidic channel ceiling 232 and thefluidic channel sidewall 236 a form an edge. The fluidic channel ceiling232 and the fluidic channel sidewall 236 b form another edge. Thefluidic channel sidewalls 236 a and 236 b have positive draft angles,for example, ranging from 1-15 degrees. The width and the height of thefluidic channel 204 shown in FIG. 4 can be 7 mm and 1.2 mm respectively.

The width of the fluidic channel 204 can be different in differentimplementations, for example, ranging from 1 mm to 20 mm. In someembodiments, the width of the fluidic channel 204 can be, or be about,1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20mm, or a number or a range between any two of these values. In someembodiments, the width of the fluidic channel 204 can be at least, or atmost, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,or 20 mm. A larger width, for example 7 mm, can increase the flowcellarea of a given flowcell length.

The height of the fluidic channel 204 can be different in differentimplementations, for example, ranging from 0.1 mm to 2 mm. In someembodiments, the height of the fluidic channel 704 can be, or be about,0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.10, 0.11, 0.12, 0.13,0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20 mm, or a number or a rangebetween any two of these values. In some embodiments, the height of thefluidic channel 204 can be at least, or at most, 0.1, 0.2, 0.3, 0.4,0.5, 0.6, 0.7, 0.8, 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17,0.18, 0.19, or 0.20 mm.

The cartridge can be designed to process more than one sample inparallel. The cartridge can further comprise one or more removablesample collection chamber(s) that are suitable for interfacing withstand-alone PCR thermal cyclers or sequencing instruments. The cartridgeitself can be suitable for interfacing with stand-alone PCR thermalcyclers or sequencing instruments. The term “cartridge” as used in thisdisclosure can be meant to include any assembly of parts which containsthe sample and beads during performance of the assay.

The cartridge can further comprise components that are designed tocreate physical or chemical barriers that prevent diffusion of (orincrease path lengths and diffusion times for) large molecules in orderto minimize cross-contamination between microwells. Examples of suchbarriers can include, but are not limited to, a pattern of serpentinechannels used for delivery of cells and solid supports (e.g., beads) tothe microwell array, a retractable platen or deformable membrane that ispressed into contact with the surface of the microwell array substrateduring lysis or incubation steps, the use of larger beads, e.g. Sephadexbeads as described previously, to block the openings of the microwells,or the release of an immiscible, hydrophobic fluid from a reservoirwithin the cartridge during lysis or incubation steps, to effectivelyseparate and compartmentalize each microwell in the array.

Cartridges can be fabricated using a variety of techniques and materialsknown to those of skill in the art. In general, the cartridges will befabricated as a series of separate component parts and subsequentlyassembled using any of a number of mechanical assemblies or bondingtechniques. Examples of suitable fabrication techniques include, but arenot limited to, conventional machining, CNC machining, injectionmolding, thermoforming, and 3D printing. Once the cartridge componentshave been fabricated they can be mechanically assembled using screws,clips, and the like, or permanently bonded using any of a variety oftechniques (depending on the choice of materials used), for example,through the use of thermal bonding/welding or any of a variety ofadhesives or adhesive films, including epoxy-based, acrylic-based,silicone-based, UV curable, polyurethane-based, or cyanoacrylate-basedadhesives.

Cartridge components can be fabricated using any of a number of suitablematerials, including but not limited to silicon, fused-silica, glass,any of a variety of polymers, e.g. polydimethylsiloxane (PDMS;elastomer), polymethylmethacrylate (PMMA), polycarbonate (PC),polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE),polyimide, cyclic olefin polymers (COP), cyclic olefin copolymers (COC),polyethylene terephthalate (PET), epoxy resins, non-stick materials suchas teflon (PTFE), metals (e.g. aluminum, stainless steel, copper,nickel, chromium, and titanium), or any combination thereof.

The inlet and outlet features of the cartridge can be designed toprovide convenient and leak-proof fluid connections with the instrument,or can serve as open reservoirs for manual pipetting of samples andreagents into or out of the cartridge. Examples of convenient mechanicaldesigns for the inlet and outlet port connectors can include, but arenot limited to, threaded connectors, Luer lock connectors, Luer slip or“slip tip” connectors, press fit connectors, and the like. The inlet andoutlet ports of the cartridge can further comprise caps, spring-loadedcovers or closures, or polymer membranes that can be opened or puncturedwhen the cartridge is positioned in the instrument, and which serve toprevent contamination of internal cartridge surfaces during storage orwhich prevent fluids from spilling when the cartridge is removed fromthe instrument. The one or more outlet ports of the cartridge canfurther comprise a removable sample collection chamber that is suitablefor interfacing with stand-alone PCR thermal cyclers or sequencinginstruments.

In some embodiments, the inlet port and the outlet port can be capableof directing a flow of a fluid through the fluidic channel, therebycontacting the microwells with the fluid. In some embodiments, thedevice comprises a pipette tip interface for loading or removing a cellsample, an assay reagent, a bead suspension, waste from the device, or acombination thereof. The device can comprise the cell sample, the assayreagent, the bead suspension, or a combination thereof.

The cartridge can include integrated miniature pumps or other fluidactuation mechanisms for control of fluid flow through the device.Examples of suitable miniature pumps or fluid actuation mechanisms caninclude, but are not limited to, electromechanically- orpneumatically-actuated miniature syringe or plunger mechanisms, membranediaphragm pumps actuated pneumatically or by an external piston,pneumatically-actuated reagent pouches or bladders, or electro-osmoticpumps.

The cartridge can include miniature valves for compartmentalizingpre-loaded reagents or controlling fluid flow through the device.Examples of suitable miniature valves can include, but are not limitedto, one-shot “valves” fabricated using wax or polymer plugs that can bemelted or dissolved, or polymer membranes that can be punctured; pinchvalves constructed using a deformable membrane and pneumatic, magnetic,electromagnetic, or electromechanical (solenoid) actuation, one-wayvalves constructed using deformable membrane flaps, and miniature gatevalves.

The cartridge can include vents for providing an escape path for trappedair or gas such as CO₂ or N₂. Vents can be constructed according to avariety of techniques, for example, using a porous plug ofpolydimethylsiloxane (PDMS) or other hydrophobic material that allowsfor capillary wicking of air or gas but blocks penetration by water.

The mechanical interface features of the cartridge can provide foreasily removable but highly precise and repeatable positioning of thecartridge relative to the instrument system. Suitable mechanicalinterface features can include, but are not limited to, alignment pins,alignment guides, mechanical stops, and the like. The mechanical designfeatures can include relief features for bringing external apparatus,e.g. magnets or optical components, into close proximity with themicrowell array chamber.

The cartridge can include temperature control components or thermalinterface features for mating to external temperature control modules.Examples of suitable temperature control elements can include, but arenot limited to, resistive heating elements, miniature infrared-emittinglight sources, Peltier heating or cooling devices, heat sinks,thermistors, thermocouples, and the like. Thermal interface features canbe fabricated from materials that are good thermal conductors (e.g.copper, gold, silver, etc.) and can comprise one or more flat surfacescapable of making good thermal contact with external heating blocks orcooling blocks.

The cartridge can include optical interface features for use in opticalimaging or spectroscopic interrogation of the microwell array. Thecartridge can include an optically transparent window, e.g. themicrowell substrate itself or the side of the flowcell or microarraychamber that is opposite the microwell array, fabricated from a materialthat meets the spectral requirements for the imaging or spectroscopictechnique used to probe the microwell array. Examples of suitableoptical window materials can include, but are not limited to, glass,fused-silica, polymethylmethacrylate (PMMA), polycarbonate (PC), cyclicolefin polymers (COP), or cyclic olefin copolymers (COC).

Loading Station and Cartridge

FIG. 5 shows the loading station 100 with the cartridge 200 positionedwithin the tray 110. As described herein, the loading station 100 canfacilitate performance of a workflow using the microwell array of themicrowell array substrate 208. For example, in some embodiments, one orboth of the inlet port components formed by inlet port components 220 aand 220 b can be configured to receive a pipette for introduction of oneor more particles or other materials. In some embodiments, the tray 110can secure the cartridge 200 within the loading station duringpipetting. In some embodiments, the tray 110 can secure the cartridge200 within the loading station during introduction and/or removal of thepipette.

As shown in FIG. 5, the actuator 140 of the loading station 100 is inits first or neutral position. As described herein, when the actuator140 is in the neutral position, both the magnet 120 and the magnet 130exert relatively weak or no force on any magnetic particles positionedin the flowcell 202 and/or microwell array of the cartridge 200. Whenrelatively weak or no magnetic force is exerted on particles positionedin the flowcell 202 and/or microwell array, the particles may be washedby fluids introduced into the flowcell 202 of the cartridge 200, forexample, through the inlet port components 220 a and 220 b. In someembodiments, fluid introduced into the flowcell 202 of the cartridge 200can wash particles within the flowcell 202 and/or microwell array bytransporting the particles out of the flowcell 202 through the outletport 224.

As shown in FIG. 5, the actuator 160 is positioned in the secondposition. As described herein, when the actuator 160 is positioned inthe second position, the drawer 150 can also be positioned in its secondposition. In some embodiments, the second position of the drawer 150 canbe designated as a waste collection position. In such embodiments, theone of the tubes 152 a or 152 b that is aligned with the outlet port 224can be designated as a waste collection tube.

A user can position the actuator 160 in its second position whencollection of waste is desirable to allow fluid and particles flowingthrough the flowcell 202 of the cartridge 200 to flow out of the outletport 224 and into the one of the tubes 152 a and 152 b aligned with theoutlet port 224.

As described herein, the actuator 160 can be transitioned to the thirdposition, which can cause the drawer 150 to transition to its thirdposition. When the drawer 150 is in its third position, the other one ofthe tubes 152 a and 152 b can align with the outlet port 224. In someembodiments, the third position of the drawer 150 can be designated asthe bead collection position. The other one of the tubes 152 a and 152 bcan be designated as the bead collection tube.

A user can position the actuator 160 in its second position whencollection of beads is desirable to allow beads within the flowcell 202and/or micro well array of the cartridge 200 to flow out of the outletport 224 and into the one of the tubes 152 a and 152 b aligned with theoutlet port 224.

FIG. 6 shows an enlarged view of the portion of the loading station 100with the cartridge 200 positioned within the tray 110. As shown in FIG.6, the loading station 100 can include a locking member 112. The lockingmember 112 can secure the cartridge 200 within the tray 110. In someembodiments, the locking member 112 is a spring clip. In someembodiments, the cartridge 200 can be secured to the tray 110 byinserting the cartridge 200 so that a portion of the cartridge 200 ispositioned between the locking member 112 and the tray 110. In someembodiments, the locking member 112 is retractable within the body 105of the loading station 100. In some embodiments, the cartridge 200 canbe secured to the tray 110 by positioning the cartridge 200 within thetray 110 and advancing the locking member 112 so that locking member 112is positioned superior to a superior surface of the cartridge 200 suchthat the cartridge 200 is positioned between the locking member 112 andthe tray 110.

FIG. 7 shows an enlarged sectional view of the loading station 100 andcartridge 200 with several components removed to show internal featuresof the loading station 100. FIG. 7 depicts the magnet 120 in itsinactive position. As described herein, the inactive position of themagnet 120 corresponds to first position of the actuator 140 as shown inFIG. 5. FIG. 7 shows a plurality of gears forming a gear mechanism 122in communication with the magnet 120. Movement of the actuator 140between its first and second position can activate the gear mechanism122 to cause movement of the magnet 120 between its inactive and activeposition.

FIG. 8 shows the loading station 100 and cartridge 200 with the actuator140 in its second position. As described herein, transition of theactuator 140 from the first position to the second position can causethe magnet 120 to transition from its inactive position to its activeposition.

FIG. 9 shows a side view of the loading station 100 and cartridge 200with several components removed to show internal features. As shown inFIG. 9, the actuator 140 is in the second position. When transitioned tothe second position, the actuator 140 can engage a gear 142. The gear142 includes a plurality of teeth 144 extending at least partiallyaround an edge of the gear 142. In some embodiments, the loading station100 can include a set of teeth 172 positioned to engage the teeth 144when the actuator 140 is transitioned from the first position to thesecond position. In some embodiments, as the actuator 140 istransitioned from its first position to its second position, theactuator 140 causes the teeth 144 to advance along the teeth 172 tocause rotation of the gear 142. In some embodiments, the gear 142 iscoupled to a shaft that is coupled to the gear mechanism 122 such thatrotation of the gear 142 causes activation of the gear mechanism 122. Asdescribed herein, activation of the gear mechanism 122 can causemovement of the magnet 120. In some embodiments, as the actuator 140transitions from the first position to the second position, the gearmechanism 122 causes the magnet 120 to transition from the inactiveposition to the active position. If the actuator 140 transitions fromthe second position to the first position, the actuator 140 can causethe gear 142 to advance along the teeth 172 so as to cause rotation ofthe gear 142 in an opposite direction of that when the actuator 140 istransitioned from the first position to the second position. In someembodiments, as the actuator 140 transitions from the second position tothe first position, the gear mechanism 122 causes the magnet 120 totransition from the active position to the inactive position.

With continued reference to FIG. 9, the loading station 100 can alsoinclude a set of teeth 174. In some embodiments, the actuator 140 can beconfigured to engage the set of teeth 174 when the actuator transitionsfrom the first position to the third position. In some embodiments, theactuator 140 can be configured to cause the set of teeth 174 totranslate within the body 104 of the loading station 100 when theactuator 140 transitions from the first position to the third position.In some embodiments, the loading station 100 can include a gear 146having a plurality of teeth 148. In some embodiments, when the actuator140 transitions between the first position to the third position, theteeth 174 can engage the teeth 148 of the gear 146 to cause the gear 146to rotate. The gear 146 can be coupled to a shaft that is also coupledto a link assembly 132. The link assembly 132 can include a plurality oflinks coupled to the magnet 130. Rotation of the gear 146 can causemovement of the link assembly 132 to cause the magnet 130 to transitionbetween the inactive position and the active position. In someembodiments, transition of the actuator 140 from the first position tothe third position causes rotation of the gear 146 such that the linkassembly 132 moves to cause the magnet 130 to transition from itsinactive position to its active position. In some embodiments,transition of the actuator 140 from the third position to the firstposition causes rotation of the gear 146 such that the link assembly 132moves to cause the magnet 130 to transition from the active position tothe inactive position. The actuator 140, gear 142, gear 146, set ofteeth 172, and set of teeth 174 can each be members of an actuationmechanism. In some embodiments, the actuator can only actuate 140 one ofthe gear 142 and gear 146 at a time. As shown in FIG. 9, in someembodiments, the actuator can only actuate one of the gear 142 and gear146 due to the relative positioning of the gear 142 and the gear 146. Insome embodiments, the actuation mechanism can be configured to couple toonly one of the gear 142 and gear 146 in any position of the actuator140. In some embodiments, the actuation mechanism can be configured tocause movement of only one of the magnet 120 and magnet 130 in anyposition.

FIG. 10 shows an enlarged sectional view of the loading station 100 andcartridge 200 with several components removed to show internal featuresof the loading station 100. FIG. 10 depicts the magnet 120 in its firstposition. In some embodiments, when the magnet 120 is in the secondposition, a superior face of the magnet 120 is in parallel with aninferior face of the cartridge 200. In some embodiments, the superiorsurface of the magnet 120 can be 1.0 mm away or approximately 1.0 mmaway from the inferior surface of the cartridge 200 when in the activeposition. In some embodiments, the superior surface of the magnet 120can be 0.5 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, less than 0.5 mm, lessthan 1.0 mm, no more than 1.0 mm, less than 1.5 mm, less than 2.0 mm,less than 2.5 mm, less than 3.0 mm, or between 0.5 mm and 1.5 mm awayfrom the inferior surface of the cartridge 200 when the magnet 120 is inthe active position. In some embodiments, the superior surface of themagnet 120 can be sized and shaped to extend to or beyond the boundariesof an active area of the flowcell 202.

FIG. 11 shows the loading station 100 and cartridge 200 with theactuator 140 in its third position. As described herein, transition ofthe actuator 140 from the first position to the third position can causethe magnet 130 to transition from the inactive position to the activeposition. FIG. 11 shows the magnet 130 in the active position. In someembodiments, when the magnet 130 is in the active position, an inferiorface of the magnet 130 can be positioned above a superior face of thecartridge 200. In some embodiments, the inferior face of the magnet 130can be in parallel with the superior face of the cartridge 200. In someembodiments, the inferior surface of the magnet 130 can be 1.0 mm awayor approximately 1.0 mm away from the superior surface of the cartridge200 when in the active position. In some embodiments, the inferiorsurface of the magnet 130 can be 0.5 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm,less than 0.5 mm, less than 1.0 mm, no more than 1.0 mm, less than 1.5mm, less than 2.0 mm, less than 2.5 mm, less than 3.0 mm, or between 0.5mm and 1.5 mm away from the superior surface of the cartridge 200 whenthe magnet 130 is in the active position. In some embodiments, theinferior surface of the magnet 130 can be sized and shaped to extend toor beyond the boundaries of the active area of the flowcell 202.

FIGS. 12A and 12B shows the loading station 100 and cartridge 200showing several components of the drawer 150 removed from the loadingstation 100. As shown in FIG. 12A, the drawer 150 can include a driptray 154. The drip tray 154 can be positioned inferior to the tubereceptacle 156. The drip tray 154 can be configured to receive liquiddripping or leaking from one or both of the tubes 152 a and 152 b. Asshown in FIG. 12A, the drip tray 154 can be removable.

As shown in FIG. 12B, the drawer 150 can include a splash shield 158. Inuse, the splash shield 158 can be positioned within the interior of thebody 105 and can at least partially surround a path of movement of thedrawer 150. The splash shield 158 can form a barrier between the tubes152 a and 152 b and other components of the loading station 100 toprevent splashing of liquid from the tubes 152 a and 152 onto othercomponents of the loading station 100.

Examples of Workflows

FIG. 12 depicts a non-limiting example of a workflow 300 that can beperformed using a loading station 100 and cartridge 200. Although theworkflow 300 is described with respect to the loading station 100 andcartridge 200, one of skill in the art would understand that the sameworkflow or a similar workflow may be performed using other embodimentsof loading stations and cartridges as described herein.

The workflow 300 describes steps performed after the cartridge 200 ispositioned within the tray 110 and the tubes 152 a and 152 b arepositioned within the drawer 150. One of skill in the art wouldrecognize that additional steps of inserting the cartridge 200 into thetray 110 and/or inserting the tubes 152 a and 152 b into the receptacle156 of the drawer 150 may be required prior to initiation of theworkflow 300 if the cartridge 200 and/or tubes 152 a and 152 b are notalready in their respective positions within the loading station 100.

Additionally, the workflow 300 describes steps performed with theactuator 140 in its first position (corresponding to each of the magnets120 and 130 being in their inactive positions) and the actuator 160 inits second position (corresponding to one of the tubes 152 a and 152 bbeing in a waste collection position) at the beginning of the workflow300. One of skill in the art would recognize that additional steps maybe required to move the actuator 140 and/or actuator 160 to their firstand second positions, respectively, prior to initiation of the workflow.

The workflow 300 can begin with a step 310 in which a plurality of cellsis introduced into a microwell array of the cartridge 200 while thecartridge 200 is positioned within the loading station 300. In someembodiments, the plurality of cells can be introduced into the cartridge200 via the inlet formed by inlet port components 220 a and 220 b. Insome embodiments, the plurality of cells can be introduced into thecartridge 200 via a pipette. In some embodiments, the plurality of cellscan enter the microwell array via the flowcell 202 of the cartridge 200.In some embodiments, each microwell in the microwell array can entraponly a single cell of the plurality of cells.

In alternative embodiments, the plurality of cells can be introducedinto the microwell array prior to positioning of the cartridge 200within the loading station 100.

After the plurality of cells are introduced into the microwell array, aplurality of barcode-bearing beads can be introduced into the microwellarray at a step 320. In some embodiments, the plurality of beads can beintroduced into the cartridge 200 via the inlet formed by inlet portcomponents 220 a and 220 b. In some embodiments, the plurality of beadscan be introduced into the cartridge 200 via a pipette. In someembodiments, the plurality of beads can enter the microwell array viathe flowcell 202 of the cartridge 200. In alternative embodiments, theplurality of beads can be introduced into the microwell array prior topositioning of the cartridge 200 within the loading station 100. Itwould be appreciated by one of skill in the art that the order in whichthe cells are introduced (block 310) and the beads are introduced (block320) occur is not particularly limited. The two steps can occurconcurrently or sequentially, and any order is within the scope of thepresent disclosure.

In some embodiments, each microwell in the microwell array can entraponly a single bead of the plurality of beads. In some embodiments, eachmicrowell in the microwell array can entrap a single cell of theplurality of cells and a single bead of the plurality of beads.

After the plurality of beads are introduced into the microwell array,cell lysis can be performed at a step 330. In some embodiments, the celllysis can be performed before the plurality of beads are introduced intothe microwell array.

Cell lysis can be accomplished by any of the variety of means describedherein. In some embodiments, step 330 includes transitioning the magnet120 to its active position prior to or during cell lysis, as shown anddescribed with respect to FIG. 10. As described herein, the magnet 130can be transitioned to its active position by moving the actuator 140 toits second position.

When the magnet 120 is in the active position, the magnet 120 canattract the barcoded-bearing beads positioned within the microwells. Dueto the positioning of the magnet 120, the magnetic field generated bythe magnet 120 can provide a magnetic force drawing the beads in theinferior direction towards the magnet 120. In some embodiments, themagnetic force generated by the magnet 120 can maintain the beads in themicrowells during lysis. In some embodiments, the beads can bedimensioned such that a bead positioned superior to a cell within amicrowell can prevent passage of the cell out of the microwell withoutremoval of the bead from the microwell. In such embodiments, themagnetic force generated by the magnet 120 can maintain the cells in themicrowells during lysis by maintaining the beads in the microwells toprevent passage of the cells.

In some embodiments, lysis is performed by introducing a lysis buffer.In such embodiments, the magnet 120 can prevent beads and/or cellspositioned within the microwells from being washed away by the lysisbuffer. In some embodiments, during cell lysis, the one of the tubes 152a and 152 b designated for waste collection can be aligned with theoutlet of the flowcell 202 to receive excess buffer flowing through theflowcell 202. In some embodiments, the introduction of cells and beadsresults in cells and/or beads positioned within the flowcell 202 butoutside of a microwell. In such embodiments, the cells and/or beadspositioned outside of the microwells may be washed away by the lysisbuffer into the one of the tubes 152 a and 152 b designated for wastecollection.

In some embodiments, after lysis, the magnet 120 is returned to itsinactive position. As described herein, the magnet can transition to theinactive position by movement of the actuator 140 from the secondposition to the first position.

In certain embodiments, a wash can be performed before, during, or aftercell lysis. In some embodiments, a wash fluid can be introduced into theflowcell 202 of the cartridge 200 via the inlet port provided by inletport components 220 a and 220 b. The wash fluid can flow through theflowcell 202 to remove beads and/or cells within the flowcell 202 butoutside of a microwell. The removed beads and/or cells can be depositedin the one of the tubes 152 a and 152 b designated for waste collectionand aligned with the outlet of the flowcell 202. During the wash, themagnet 120 can be maintained in the active position. The magnetic forceprovided by the magnet 120 can prevent the beads and/or cells positionedwithin the microwells from removal by the wash fluid. In embodiments inwhich a wash is performed after cell lysis, the magnet 120 can bereturned to its inactive position following the wash.

After cell lysis, the barcode-bearing beads can be retrieved at step340. In some embodiments, the barcode-bearing beads are retrieved byadvancing the magnet 130 from its inactive position to its activeposition. As described herein, the magnet 130 can be advanced from itsinactive position to its active position by movement of the actuator 140between the first position and the third position.

When the magnet 130 is positioned in the active position, the magnet 130can attract the barcode-bearing beads positioned within the microwells.In some embodiments, the magnetic force exerted on the barcode-bearingbeads by the magnet 130 can be sufficient to remove the barcode bearingbeads from the microwells. When the barcode-bearing beads are removed bythe magnet 130, the cells may remain within the microwells. In someembodiments, the magnetic force exerted on the barcode-bearing beads bythe magnet 130 can cause the barcode bearing beads to move towards thesuperior surface of the cartridge 200. The magnetic force exerted by themagnet 130 can maintain the beads in a position superior to themicrowells. While the beads are maintained in a position superior to themicrowells, the beads can be said to be retrieved by the magnet 130.

While the beads are maintained in a position superior to the microwellsby the magnet 130, a wash can be performed. In some embodiments, a washfluid can be introduced into the flowcell 202 of the cartridge 200 viathe inlet port provided by inlet port. The wash fluid can flow throughthe flowcell 202 to remove the cells in the microwells. The cells can bedeposited in the one of the tubes 152 a and 152 b designated for wastecollection and aligned with the outlet of the flowcell 202. Washing thecells from the microwells can allow for later collection of only thebeads previously positioned in the microwells.

After the beads are retrieved by the magnet 130, the beads can becollected at step 350. In some embodiments, the magnet 130 istransitioned from its active position to its inactive position,releasing the beads from their maintained position superior to themicrowells. As described herein the magnet 130 can be transitioned fromits active position to its inactive position by movement of the actuator140 from its third position to its first position. In some embodiments,upon release, the beads drop or return into the same microwells fromwhich they were removed.

After the beads are released, the one of the tubes 152 a and 152 bdesignated for bead collection can be aligned with the outlet port 224of the cartridge 200. As described herein, the tube 152 a or 152 bdesignated for bead collection can be aligned with the outlet port 224by transitioning the actuator 160 from its second position to its thirdposition. After the tube 152 a or 152 b designated for bead collectionis aligned with the outlet port 224 a, a fluid can be advanced throughthe flowcell 202 to cause the beads to flow out of the outlet port 224and into the collection tube 152 a or 152 b designated for beadcollection. To allow collection of the beads, it can be desirable thateach of the magnets 120 and 130 are positioned in their respectiveinactive positions during collection. In other words, it can bedesirable that neither magnet 120 nor magnet 130 is exerting a magneticforce on the beads during collection.

After the beads are collected, the workflow 300 concludes. In someembodiments, after collection of the beads, the tube 152 a or 152 bdesignated for bead collection can be removed from the loading station100 for further processing and/or analysis of the beads.

The workflow 300 describes one example of a workflow that can beperformed using the loading station 100 and cartridge 200. However, theloading station 100 can be used to perform different workflows. In someembodiments, the loading station 100 can be used to perform workflows ondifferent cartridges.

One of skill in the art would also recognize that various alternativeembodiments of the loading station 100 can be used to perform the stepsof the workflow 300 or other procedures described herein. In someembodiments, the loading station 100 may include only a single magnetconfigured to move over a range of positions. For example, in someembodiments, the single magnet can be movable to the active position ofthe magnet 120 during performance of a lysis step, such as step 330. Insome embodiments, the single magnet can be movable to the activeposition of magnet 130 during a retrieval step such as step 340. Incertain embodiments, the single magnet can be moved to one or more otherpositions in which the single magnet does not exert a force or exerts arelatively weak force on the beads, for example, during a beadintroduction step, such as step 320, or during a bead collection step,such as step 350. In some embodiments, the loading station 100 can havemore than two magnets. In some embodiments, each magnet can have aseparate actuator for transitioning between its inactive position andactive position.

In at least some of the previously described embodiments, one or moreelements used in an embodiment can interchangeably be used in anotherembodiment unless such a replacement is not technically feasible. Itwill be appreciated by those skilled in the art that various otheromissions, additions and modifications may be made to the methods andstructures described above without departing from the scope of theclaimed subject matter. All such modifications and changes are intendedto fall within the scope of the subject matter, as defined by theappended claims.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity. As used in this specification and the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. Any reference to “or” herein isintended to encompass “and/or” unless otherwise stated.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible sub-rangesand combinations of sub-ranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeinclude the number recited and refer to ranges which can be subsequentlybroken down into sub-ranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember. Thus, for example, a group having 1-3 articles refers to groupshaving 1, 2, or 3 articles. Similarly, a group having 1-5 articlesrefers to groups having 1, 2, 3, 4, or 5 articles, and so forth.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

What is claimed is:
 1. A loading station comprising: a tray configuredto receive a microwell array; a first magnet, the first magnet beingmovable between a first magnet active position in which the first magnetis positioned to exert a first magnetic force in a first direction onone or more magnetic particles positioned within the microwell array anda first magnet inactive position in which the first magnet is positionedto exert less magnetic force on the one or more magnetic particlespositioned within the microwell array in comparison to the first magnetactive position, wherein the first magnet is positioned inferior to thetray when the first magnet is in the first magnet active position; asecond magnet, the second magnet being movable between a second magnetactive position in which the second magnet is positioned to exert asecond magnetic force in a second direction on the one or more magneticparticles positioned within the microwell array and a second magnetinactive position in which the second magnet is positioned to exert lessmagnetic force on the one or more magnetic particles positioned withinthe microwell array in comparison to the second magnet active position,wherein the second direction of the second magnetic force is differentthan the first direction of the first magnetic force; and an actuationmechanism configured to cause movement of at least one of the firstmagnet and the second magnet.
 2. The loading station of claim 1, whereinthe actuation mechanism comprises an actuator, the actuator beingmovable between a plurality of different positions, wherein at leastsome movements of the actuator cause movement of the first magnetbetween the first magnet active position and the first magnet inactiveposition, and wherein at least some movements of the actuator causemovement of the second magnet between the second magnet active positionand the second magnet inactive position.
 3. The loading station of claim2, wherein at least one of the first magnet and the second magnet arecoupled to the actuation mechanism such that when the first magnet is inthe first magnet active position, the second magnet is not in the secondmagnet active position and when the second magnet is in the secondmagnet active position, the first magnet is not in the first magnetactive position.
 4. The loading station of claim 2, wherein eachmovement of the actuator is configured to cause the movement of no morethan one of the first magnet and the second magnet.
 5. The loadingstation of claim 1, wherein the actuation mechanism comprises one ormore members coupled to the first magnet and one or more members coupledto the second magnet.
 6. The loading station of claim 5, wherein theactuator is configured to couple to the one or more members coupled toone of the first magnet or the second magnet in at least some of theplurality of different positions of the actuator, wherein the actuatoris configured to decouple from the one or more members coupled to theone of the first magnet and the second magnet in at least some of theplurality of different positions.
 7. The loading station of claim 1,further comprising a drawer configured to hold one or more tubes, thedrawer being movable between a plurality of different positions.
 8. Theloading station of claim 7, wherein the drawer is movable to at leastone position in which at least one of the one or more tubes ispositioned to align with an outlet of the microwell.
 9. The loadingstation of claim 7, further comprising a drawer actuator, the draweractuator being movable between a plurality of different positions,wherein at least some movements of the drawer actuator cause movement ofthe drawer.
 10. The loading station of claim 1, wherein microwell arrayis housed within a cartridge and the tray is configured to receive thecartridge housing the microwell array.
 11. The loading station of claim1 in combination with a cartridge positioned within the tray of theloading station, the cartridge comprising a flowcell, wherein theflowcell comprises the microwell array.
 12. The loading station of claim11, wherein a superior surface of the first magnet is separated from aninferior surface of the flowcell by a distance of no more than 1.0 mmwhen the first magnet is positioned in the first magnet active position.13. The loading station of claim 11, wherein an inferior surface of thesecond magnet is separated from a superior surface of the flowcell by adistance of no more than 1.0 mm when the second magnet is positioned inthe second magnet active position.
 14. The loading station of claim 11,wherein a superior surface of the first magnet is parallel to aninferior surface of the cartridge when the first magnet is in the firstmagnet active position.
 15. The loading station of claim 11, wherein aninferior surface of the second magnet is parallel to a superior surfaceof the cartridge when the second magnet is in the second magnet activeposition.
 16. The loading station of claim 11, further comprising alocking mechanism configured to releasably secure the cartridge withinthe tray.
 17. A method for collecting a plurality of barcode-bearingbeads comprising: introducing a plurality of cells into a flowcell of acartridge positioned within a loading station; introducing a pluralityof magnetic barcode-bearing beads into the flowcell, wherein theflowcell comprises a plurality of microwells, wherein each microwell isdimensioned to receive at least one cell of the plurality of cells andat least one magnetic barcode-bearing bead of the plurality of magneticbarcode-bearing beads; moving a first magnet of the loading station to aposition sufficient to exert a first magnetic force on at least some ofthe magnetic barcode-bearing beads positioned within the plurality ofmicrowells in a first direction; moving a second magnet of the loadingstation to a position sufficient to exert a second magnetic force on atleast some of the magnetic barcode-bearing beads positioned within theplurality of microwells in a second direction different than the firstdirection; and introducing a fluid into the flowcell to cause at leastsome of the barcode-bearing beads to flow through the flowcell.
 18. Themethod of claim 17, wherein at least one of the first magnetic force andthe second magnetic force are of a magnitude sufficient to preventmagnetic barcode-bearing beads on which the at least one of the firstmagnetic force and second magnetic force are exerted from flowingthrough the flowcell when the fluid is introduced into the flowcell. 19.The method of claim 17, wherein each of the first magnet and the secondmagnet are coupled to an actuation mechanism comprising an actuator. 20.The method of claim 19, wherein moving the first magnet of the loadingstation to exert a first magnetic force on at least some of the magneticbarcode-bearing beads positioned within the plurality of microwells in afirst direction comprises moving the actuator to a first actuatorposition.
 21. The method of claim 20, wherein moving the second magnetof the loading station to exert a second magnetic force on at least someof the magnetic barcode-bearing beads positioned within the plurality ofmicrowells in a second direction different than the first directioncomprises moving the actuator to a second actuator position from thefirst actuator position.
 22. The method of claim 21, wherein moving theactuator from the first actuator position to the second actuatorposition causes the first magnet to move to a position in which lessmagnetic force is exerted on the at least some of the magneticbarcode-bearing beads positioned within the plurality of microwells bythe first magnet than when the actuator is positioned within the firstposition.